Strongly Coupled MRI Coil Loops SNR Improvement
Solution Overview
Problem
Current MRI systems face challenges in achieving an improved signal-to-noise ratio (SNR) from received signals due to mutual inductance between overlapping or concentric coil loops, which affects the quality of magnetic-resonance imaging.
Innovation Solution
The use of strongly coupled overlapped and/or concentric radio-frequency (RF) MRI coils with independent receive pre-amplifiers and a signal combiner-subtractor to subtract a suitably adjusted copy of the transmit pulse from the received signal, improving SNR by decoding common-mode signals and adjusting the phase and amplitude of signals from multiple coil loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If overlapping or concentric coil loops are used in MRI systems, then spatial coverage and imaging capability are improved, but mutual inductance interference increases and signal-to-noise ratio deteriorates
Solution Approach 1:
The patent divides the coil system into separate transmit and receive coil loops that can be independently controlled and processed. Each coil loop is treated as an independent segment with its own preamplifier, allowing separate optimization of transmit and receive functions while maintaining spatial coverage through the overlapping/concentric configuration.
Solution Approach 2:
The patent extracts and removes the harmful mutual inductance interference signal from the received signal using a combiner-subtractor circuit. The transmit pulse signal is subtracted from the received signal to eliminate the coupled interference, leaving only the desired NMR signal from the sample.
2Measurement precision
If strongly coupled coil loops are used, then signal extraction capability is improved, but signal-to-noise ratio worsens due to mutual inductance
Solution Approach 1:
The patent introduces a combiner-subtractor circuit as an intermediary between the coil loops and the signal processing system. This intermediary device processes the signals from multiple coil loops, subtracts the mutual inductance interference, and outputs a cleaned signal with improved signal-to-noise ratio while maintaining the ability to extract signals from strongly coupled loops.
Solution Approach 2:
The patent creates a copy of the transmit pulse signal and uses it in the subtraction process to remove the mutual inductance interference. By copying the known transmit signal and subtracting it from the received signal, the system eliminates the interfering component while preserving the desired NMR signal.
3Reliability
If multiple coil loops with independent preamplifiers are used, then signal reception capability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple coil loops with independent preamplifiers into a unified receive system using a combiner-subtractor circuit. This merging approach maintains the reliability benefits of independent preamplifiers for each coil while integrating their outputs through a single combiner circuit that also performs the interference subtraction function.
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 enhances the signal-to-noise ratio (SNR) of received signals by effectively removing mutual inductance interference, leading to improved image quality in MRI systems.
Implementation Method 1
a receive loop that receives a signal from the transmit loop
Implementation Method 2
a combiner-subtractor to subtract a suitably adjusted copy of the transmit pulse from the received signal
Data Source
AI summary
A method and apparatus for processing radio-frequency (RF) signals suitable for magnetic-resonance imaging (MRI) and/or magnetic-resonance spectroscopy (MRS) from radio-frequency (RF) coils that have strongly-coupled coil loop pairs, each pair including a transmit loop and a receive loop, wherein the transmit loop and the receive loop are of equal sizes and shapes and in close proximity to each other, and wherein a suitable attenuated and phase-adjusted version of a transmit pulse is subtracted from a receive signal obtained from tissue being examined to improve signal-to-noise ratio (SNR) of the received signal.