Wireless Clock Synchronization for MRI Using Standing Wave Resonator

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Solution Overview

Problem

Wireless-type RF coils in MRI and MRS systems face challenges in clock synchronization due to motion-induced phase noise, leading to image degradation, and existing solutions rely on wired or optical cables to ensure accuracy.

Innovation Solution

A wireless clock synchronization system using first and second transmission antennas positioned at opposed ends of a main magnet to create a standing wave signal pattern within the main bore, allowing the RF portion to receive and synchronize with the clock signal, reducing phase noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If wireless-type RF coils are used to eliminate galvanic cables, then signal noise and heating are reduced, but clock synchronization accuracy deteriorates due to motion-induced phase noise

Engineering Contradiction:
Improvesignal noiseVSAvoidclock synchronization accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

A standing wave resonator is introduced as an intermediary system between the transmission antennas and the wireless RF coil. The resonator creates a controlled electromagnetic environment where the clock signal propagates through a standing wave pattern, making the signal less sensitive to receiver position variations. This mediator structure enables wireless transmission while maintaining synchronization accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system utilizes periodic electromagnetic waves at a specific resonant frequency to create a standing wave pattern within the resonator. This periodic action establishes stable nodes and antinodes in the electromagnetic field, providing a consistent reference for clock synchronization that is insensitive to small motions of the wireless receiver.

Inventive Principle:
Principle #19Periodic action

2Device complexity

If wireless transmission is used for clock synchronization, then device complexity is reduced by eliminating cables, but phase noise increases due to motion of the receiver and patient

Engineering Contradiction:
Improvecable structureVSAvoidphase noise level
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The standing wave resonator serves as a mediator that decouples the clock signal transmission from the physical position of the wireless receiver. By creating a distributed electromagnetic field with stable phase characteristics, the resonator allows wireless transmission without cables while maintaining phase stability despite receiver or patient motion.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the transmission mode from direct wireless transmission to resonant standing wave transmission. By operating at a specific resonant frequency and creating a standing wave pattern, the electromagnetic field parameters are optimized to minimize phase sensitivity to position changes, thereby reducing motion-induced phase noise.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a single transmission antenna is used, then device complexity is minimized, but synchronization accuracy deteriorates due to motion-induced time variations

Engineering Contradiction:
Improveantenna configurationVSAvoidsynchronization accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The transmission system is segmented into multiple transmission antennas positioned at opposite ends of the bore. Each antenna contributes to forming the standing wave pattern, and their combined operation creates a more stable electromagnetic environment for clock signal transmission, reducing the impact of receiver motion on synchronization accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple transmission antennas are merged to operate in conjunction with each other, creating a unified standing wave resonator system. The combined electromagnetic fields from multiple antennas establish a stable resonant mode that provides robust clock signal transmission insensitive to receiver position variations.

Inventive Principle:
Principle #5Merging (Combining)

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 minimizes phase noise in the recovered clock signal, enhancing image clarity by maintaining low root-mean-squared phase error, thus preventing image artifacts caused by motion during MRI and MRS procedures.

Implementation Method 1

the first and second transmission antennas may further be configured relative to the main bore such that the transmitted clock synchronization signal forms a standing wave signal pattern within at least a portion of the main bore of the main magnet

Methodology Applied
Scientific EffectStanding wave: Resonance

Implementation Method 2

the at least one wireless reception antenna situated within the main bore of the main magnet and configured to receive the clock synchronization signal transmitted by the first and second transmission antennas

Methodology Applied
Scientific EffectElectromagnetic radiation reception: Electromagnetic Induction

Data Source

PatentEP3126863B1Wireless clock synchronization system for magnetic resonance imaging systems and method of operation
Publication Date: 2023.10.18 KONINKLIJKE PHILIPS NV
  • EP3126863B1 patent drawingFigure 1
  • EP3126863B1 patent drawingFigure 2
  • EP3126863B1 patent drawingFigure 3~4B

AI summary

A synchronization system (100, 200, 400A, 400B, 600) for magnetic resonance (MR) systems. The synchronization system including: a main magnet (104, 404, 692) having a main bore (113, 413) and opposed first and second ends (114); a system controller (110, 610) configured to generate a clock synchronization signal in accordance with a system clock; first and second transmission antennas (132,432, TX1, TX2) at opposite ends of the main magnet and configured to transmit the clock synchronization signal into the main bore of the main magnet; and a radio frequency (RF) portion (120, 660) comprising at least one reception antenna (136, RX1) and a synchronizer (122), the at least one reception antenna situated within the main bore of the main magnet and configured to receive the clock synchronization signal transmitted by the first and second transmission antennas, and the synchronizer coupled to the at least reception antenna and configured to synchronize a clock of the RF portion in accordance with the received clock synchronization signal.