MRI Balanced Mixer Reduces Cable Heat and Bulk
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Solution Overview
Problem
The existing MRI systems face challenges with the management and comfort of a large bundle of coaxial cables used for transmitting signals from local RF coils, which can cause patient discomfort and heat issues due to induced currents, and require cumbersome connectors for multi-coaxial connections.
Innovation Solution
A balanced mixer system comprising an RF coil, a preamplifier module with an amplifier and diode array, and an intermediate frequency (IF) circuit, where an oscillator circuit supplies an oscillating signal to the diode array via a transmission line to generate an IF signal with a lower frequency, simplifying signal transfer and reducing cable complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coaxial cables are used to transmit signals from RF coils to the MRI system, then signal transmission is achieved, but patient comfort deteriorates and cable management becomes complex
Solution Approach 1:
The patent combines multiple coaxial cables into a single coaxial cable by integrating multiple RF coil signals at the coil level using combiners. This merging approach maintains signal transmission reliability while dramatically simplifying cable management, as only one cable needs to be routed through the movable patient bed rather than multiple separate cables.
Solution Approach 2:
The patent segments the signal processing function to occur at the RF coil level rather than at the central MRI system. By placing combiners and mixing circuits at the coil level, the system processes multiple coil signals locally and transmits only the combined result through a single cable, reducing cable complexity while preserving signal integrity.
2Temperature
If low-attenuation cables are used to avoid heat generation, then heat issues are reduced, but cable diameter increases making cables unwieldy
Solution Approach 1:
By combining multiple RF coil signals at the coil level before transmission, the patent reduces the total signal power that must be transmitted through the cable. This allows the use of smaller-diameter cables with higher attenuation characteristics, as the combined signal requires less power transmission capability, thereby avoiding the unwieldy large-diameter cables while still managing heat generation.
3Adaptability or versatility
If multiple coaxial cables are used for multiple RF coils, then each coil can be independently connected, but the bundle becomes large and uncomfortable for the patient
Solution Approach 1:
The patent merges multiple independent coil connections into a single cable connection by implementing combiners at the coil level. Each coil maintains its independent signal processing capability, but the physical cable infrastructure is consolidated into one bundle, dramatically reducing the weight and discomfort for the patient while preserving coil-level adaptability.
4Ease of operation
If coaxial cables are directed within a movable patient bed, then patient positioning is enabled, but induced currents cause cable heating
Solution Approach 1:
By combining multiple RF coil signals at the coil level before transmission through the movable patient bed cable, the patent reduces the total power and current that must be transmitted through the cable. This signal combination approach enables patient positioning functionality while minimizing induced currents and cable heating, as the consolidated signal requires lower transmission power.
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 solution simplifies the transfer of MR signals, reduces cable heat and bulk, and enhances operational ease by using a balanced mixer to convert high-frequency signals to lower intermediate frequencies, thereby improving patient comfort and reducing the complexity of cable management.
Implementation Method 1
the diode array to mix the oscillating signal with the first signal to generate an IF signal to be received by the IF circuit
Implementation Method 2
an amplifier configured to amplify a magnitude of a first signal from the RF coil
Data Source
AI summary
A magnetic resonance imaging (MRI) apparatus includes an RF coil, a preamplifier module, and a hub coupled to the preamplifier module via a transmission line. The preamplifier module includes an amplifier configured to amplify a magnitude of a first signal from the RF coil, the first signal having a first frequency and a diode array coupled to the amplifier. The MRI apparatus also includes an intermediate frequency (IF) circuit coupled to the transmission line and an oscillator circuit coupled to the hub and configured to supply an oscillating signal to the diode array via the transmission line to cause the diode array to mix the oscillating signal with the first signal to generate an IF signal to be received by the IF circuit via the transmission line, wherein the IF signal has a second frequency that is lower than the first frequency.