Single-Layer MRI RF Coil with Induced Current Failsafe Protection
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Solution Overview
Problem
Conventional MRI RF coils face issues with induced currents when not connected to an MRI system, leading to potential damage or safety hazards due to unintended resonance with transmit fields, and existing dual-layer inductively coupled coils are complex, costly, and reduce signal quality.
Innovation Solution
A single-layer MRI RF coil design with integrated failsafe mechanisms, such as fuses and PIN diode circuits, that can disconnect from resonance when excessive currents are detected, and an identification circuit to prevent resonance when disconnected from the MRI system, ensuring safety and reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a disconnected MRI coil is left in the vicinity of an MRI system without Tx decoupling means, then the coil can be easily stored or misplaced, but large induced currents may be caused to flow within the disconnected coil by a transmit field, damaging the coil or presenting safety risks
Solution Approach 1:
The patent implements a failsafe circuit that proactively monitors the operational state of the MRI coil and preemptively activates decoupling mechanisms when disconnection is detected, preventing harmful induced currents before they can occur during transmit operations
Solution Approach 2:
The patent employs a state detection system that continuously monitors whether the coil is properly connected to the MRI system, and based on this feedback, automatically controls the decoupling switches to enable or disable the coil's resonant circuit, thereby preventing induced currents when disconnected
2Use of energy by moving object
If a conventional dual-layer inductively coupled coil is used to mitigate SAR issues, then local RF energy transmission efficiency is improved, but the coil becomes complex and expensive with multiple decoupling circuits and control circuits
Solution Approach 1:
The patent extracts and eliminates the complex dual-layer structure and multiple decoupling circuits from the conventional design, retaining only the essential single-layer coil with a simplified failsafe circuit that provides both safety protection and adequate RF energy transmission without the need for complex control systems
Solution Approach 2:
The patent combines the safety protection function and RF energy transmission function into a single integrated coil structure with a unified control mechanism, eliminating the need for separate decoupling circuits and control systems that would be required in a dual-layer configuration
3Reliability
If multiple decoupling circuits and complex control circuits are added to a dual-layer coil, then Tx mode safety is improved, but the signal to noise ratio decreases and image quality is reduced
Solution Approach 1:
The patent employs a simple, inexpensive failsafe circuit with basic state detection and decoupling switches that provides adequate safety protection without the complexity of multiple decoupling circuits, thereby maintaining high signal-to-noise ratio and image quality while ensuring Tx mode safety
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 solution effectively prevents damage to the MRI RF coil and ensures safety by automatically disconnecting from resonance when not connected to the MRI system, while simplifying the design and improving signal quality by reducing noise and complexity.
Implementation Method 1
The LC circuit may resonate with a primary coil during a transmit mode
Implementation Method 2
The LC coil, upon resonating with the primary coil, generates a local amplified transmitting field based on an induced current
Implementation Method 3
an induced current in the LC coil may be monitored to determine whether the induced current satisfies a safety criterion
Data Source
AI summary
A single-layer magnetic resonance imaging (MRI) radio frequency (RF) coil element configured to operate in a transmit (Tx) mode and a receive (Rx) mode, the coil element comprising: an LC coil and a failsafe circuit electrically connected with the LC coil, where the LC coil, upon resonating with a primary coil of an MRI system, generates a local amplified Tx field based on an induced current generated in the LC coil by inductive coupling between the LC coil and the primary coil, where the failsafe circuit provides, upon injection of a forward DC bias current into the failsafe circuit, a first impedance, and upon the absence of the forward DC bias current, a second, higher impedance; where the failsafe circuit, upon the single-layer MRI RF coil array element being disconnected from an MRI system, provides the second, higher impedance, and reduces the magnitude of the induced current.