Wireless MRI Local Coil with Capacitive Energy Extraction
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Solution Overview
Problem
Magnetic resonance imaging systems face challenges in handling cable connections for local coils during patient movement, necessitating wireless operation and energy transmission to avoid interference with active implants and improve signal-to-noise ratio.
Innovation Solution
A local coil with a receiving mechanism for wireless energy and signal transmission using an electrical alternating voltage field, where the field source and sink are arranged to minimize penetration into the patient, employing phased locked loops and capacitive antennas to optimize energy extraction while minimizing interaction with implants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cable connections are used for local coils, then the local coil can be supplied with operating energy and transmit signals, but the cable routing becomes difficult to handle when the test subject needs to be moved
Solution Approach 1:
The patent extracts the cable connection requirement by implementing wireless energy and signal transmission. The local coil is equipped with a receiving mechanism that wirelessly receives operating energy and reference signals from the magnetic resonance imaging system, eliminating the need for physical cable connections and enabling free movement of the test subject.
Solution Approach 2:
The patent introduces an electromagnetic field as an intermediary to transfer energy and signals between the magnetic resonance imaging system and the local coil. The receiving mechanism in the local coil and the transmitting mechanism in the system use electromagnetic coupling to enable wireless communication and power transfer.
2Ease of operation
If electromagnetic signals are used for wireless transmission of operating energy, then the local coil can be operated wirelessly, but the electromagnetic signals may penetrate the object under investigation or interact with components of the local coil and active implants
Solution Approach 1:
The patent changes the frequency parameter of the electromagnetic signals used for wireless transmission. By operating at frequencies different from the Larmor frequency (e.g., lower frequencies), the system achieves wireless power transfer while minimizing interference with active implants that are typically designed to be immune to Larmor frequency signals.
Solution Approach 2:
The patent applies frequency-selective measures and stop filters at specific locations in the signal path to create local immunity characteristics. The receiving mechanism includes filtering components that selectively reject frequencies known to interfere with active implants while passing the operating frequencies needed for local coil operation.
3Measurement precision
If local coils are placed in the immediate vicinity of the object under investigation, then the signal-to-noise ratio is improved, but cable connections must be adapted when the test subject is rearranged
Solution Approach 1:
The patent removes the cable routing complexity by extracting the physical connection requirement. The wireless receiving mechanism allows the local coil to maintain its optimal position close to the test subject for high signal-to-noise ratio without being constrained by cable management issues during patient repositioning.
4Reliability
If immunity to transmission frequencies is developed for active implants, then safe wireless operation may be achieved, but the immunity must be carefully checked and generated with stop filters
Solution Approach 1:
The patent changes the operating frequency parameter to values that are inherently safer for implant carriers. By using frequencies significantly different from the Larmor frequency (such as lower frequency bands), the system achieves reliable wireless operation without requiring complex filtering, as these frequencies do not resonate with implant components.
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 wireless operation of local coils without cable adaptation, reduces interference with active implants, and improves energy extraction efficiency while controlling patient heating, ensuring safe and effective magnetic resonance imaging.
Implementation Method 1
The local coil has a receiving mechanism for taking operating energy and/or of a signal from a supply field which is embodied as an electrical alternating voltage field between a field source and a field sink
Implementation Method 2
In the local coil, reconstruction of the reference time signal and, for example, stabilization of this basic clock rate of the magnetic resonance imaging system may take place via so-called phased locked loops (PLLs)
Implementation Method 3
The Larmor frequency is determined by the properties of the material investigated and scaled with the strength of the basic magnetic field B0. For magnetic resonance measurements on biological examination objects, electromagnetic HF pulses with a Larmor frequency of 42.6 MHz and corresponding multiples may be used
Data Source
AI summary
A local coil for a magnetic resonance imaging system for acquisition of magnetic resonance signals includes a receiving mechanism for wireless transmission of operating energy of the local coil and/or a signal of the magnetic resonance imaging system. The receiving mechanism is configured to take the operating energy and/or the signal from a supply field. A magnetic resonance imaging system is also provided. The magnetic resonance imaging system includes a transmitting mechanism for wireless transmission of operating energy of a local coil and/or a signal of the magnetic resonance imaging system. The transmitting mechanism has a transmission signal generator that is connected to a field source and a field sink. The transmitting mechanism is constructed such that, in operation, the operating energy and/or the signal is transmitted by a supply field that is present as an electrical alternating voltage field between the field source and the field sink.