MR Interference Suppression via Simulation-Based Resting Periods
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Solution Overview
Problem
Magnetic resonance tomography (MRT) systems face significant overheads and complexity in adapting interference suppression due to varying MR sequence lengths and times, leading to unreliable interference reduction and increased costs from complex shielding requirements.
Innovation Solution
The method simulates the temporal and spatial course of transverse magnetization during an MR sequence to determine resting periods, allowing for the calculation of interference suppression parameters based on analysis signals, which are then used to generate an interference-suppressed MR signal by combining signals from main and auxiliary receiving antennas with optimized weighting factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex shielding booths are installed to reduce external interference signals, then the signal-noise ratio is improved, but the costs and structural restrictions increase due to space requirements
Solution Approach 1:
The harmful interference signal is extracted from the combined signal by using auxiliary receiving antennas that are specifically positioned to receive primarily interference signals. This extracted interference signal is then used to suppress the corresponding interference component in the main receiving antenna's signal, thereby improving the signal-noise ratio without requiring complex shielding booths
Solution Approach 2:
Auxiliary receiving antennas serve as intermediary devices that capture interference signals which then mediate the suppression process. These auxiliary antennas act as intermediaries between the external interference sources and the main receiving antenna, enabling interference cancellation through signal combination and weighting without physical shielding
2Reliability
If interference suppression is adapted individually to each MRT sequence, then the interference reduction effectiveness is improved, but the overheads increase
Solution Approach 1:
The system performs preliminary determination of interference signals during resting periods before actual MR signal acquisition. By identifying and characterizing interference signals in advance during these idle periods, the system prepares interference suppression parameters that can be applied during subsequent MR sequencing without requiring time-consuming adaptation for each sequence
Solution Approach 2:
The interference suppression mechanism is designed to be universally applicable across different MRT sequences. The same auxiliary receiving antennas and suppression algorithm work for all sequences, and interference signals determined during resting periods can be reused across multiple sequences, eliminating the need for individual adaptation while maintaining effectiveness
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 reduces overheads and achieves effective interference reduction with minimal adaptation overheads, potentially eliminating the need for complex shielding booths, thereby saving costs and installation space.
Implementation Method 1
Magnetic resonance tomography systems, MRT (also MRI), are imaging apparatuses which, for imaging an examination object, align nuclear spins of the examination object with a strong external magnetic field and, by an alternating magnetic field, excite them to precession about the corresponding alignment. The precession, or return, of the spins from this excited state to a state with less energy in turn generates, in response, a magnetic alternating field, which is detected by receiving antennas.
Implementation Method 2
A simulation of a predetermined MR sequence for an object is carried out by a computing unit (computer or processor), for example of the MRT system, in order to determine at least one simulation signal relating to a temporal and spatial course of the transverse magnetization of an ensemble of nuclear spins of the object.
Implementation Method 3
The main receiving antenna receives an MR signal during MR recording outside the analysis period and the at least one auxiliary receiving antenna in each case receives an interference signal outside the analysis period during the MR recording. An interference-suppressed MR signal is generated, in particular by the interference suppression facility, based on the MR signal, the interference signals and the at least one interference suppression parameter.
Data Source
AI summary
An MR sequence for an object is simulated by a computing unit in order to determine a simulation signal relating to a course of a transverse magnetization of nuclear spins. Depending on the simulation signal, a resting period of the MR sequence is determined during which an expected MR signal amplitude is always less than or equal to a predetermined limit value. An MR recording is carried out in accordance with the MR sequence, wherein an analysis signal is received in each case by a main receiving antenna and at least one auxiliary receiving antenna during an analysis period corresponding to the resting period and at least one interference suppression parameter is determined in dependence on the analysis signals. An MR signal is received by the main receiving antenna and an interference signal is received in each case by the at least one auxiliary receiving antenna. An interference-suppressed MR signal is generated based on the MR signal, the interference signals and the at least one interference suppression parameter.