MRI Ferromagnetic Particle Positioning via Intermediate Gradient Stabilization
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Solution Overview
Problem
Existing methods for determining the position of ferromagnetic particles in liquid matrices, such as blood or lubricating oils, using MRI systems are unreliable due to particle blurring or disappearance, especially when external forces like gravity and liquid flow cause drift during measurement sequences.
Innovation Solution
Implementing a measurement sequence with intermediate gradients that stabilize the particle's position between individual measurements, ensuring it remains at a consistent mean position throughout the sequence, thereby reducing or eliminating drift and maintaining accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MRI measurement sequences are used to determine particle position, then non-invasive imaging is achieved, but particle blurring and disappearance occur due to drift during measurement
Solution Approach 1:
The patent applies preliminary anti-action by using intermediate gradients to counteract external forces (gravity, flow) before they can cause significant particle drift during the measurement sequence. These gradients are applied between individual measurements to preemptively stabilize the particle position, preventing the blurring and disappearance problems that would otherwise occur during the measurement process.
2Measurement precision
If measurement sequences with multiple individual measurements are used, then position information accuracy improves, but particle drift increases during the sequence
Solution Approach 1:
The patent implements periodic action by applying intermediate gradients between individual measurements within the measurement sequence. This periodic stabilization approach counteracts drift that accumulates over time, allowing the measurement sequence to maintain precision throughout its duration. The intermediate gradients are applied at regular intervals (between each individual measurement) to continuously correct particle position without interrupting the overall measurement process.
3Adaptability or versatility
If external forces (gravity, flow) act on the particle, then natural movement occurs, but position stability during measurement deteriorates
Solution Approach 1:
The patent uses intermediate gradients as an intermediary mechanism to mediate between external forces and the particle. Rather than eliminating external forces or completely restraining the particle, the intermediate gradients act as a controlling intermediary that allows natural movement capability while providing stabilization during critical measurement periods. This intermediary approach maintains adaptability while ensuring position stability when needed.
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 allows for precise and reliable determination and positioning of ferromagnetic particles within liquid matrices by compensating for external forces, ensuring the particle remains within the measurement volume and maintaining positional accuracy over the entire sequence.
Implementation Method 1
For ferromagnetic particles, there is the possibility of exerting a force on them from the outside by means of a magnetic field gradient. This makes it possible to move the ferromagnetic particle.
Implementation Method 2
In a pause in the spatial coding, an intermediate gradient is switched with the MRI system. The intermediate gradients are sized to maintain the particle at substantially the same time averaged position over each measurement block.
Implementation Method 3
an MRI measurement sequence is applied to a measurement volume in which the particle is located, the measurement sequence comprising a plurality of individual measurements
Data Source
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Figure 3a~3b
AI summary
A method for determining the position of at least one ferromagnetic particle (30) in a liquid matrix (31) using an MRI system (50), wherein an MRI measurement sequence (MS1, MS2) is applied to a measurement volume (52) (20) in which the particle (30) is located, is characterized in that the measurement sequence (MS1, MS2) comprises a plurality of individual measurements (E1, E2) during which a spatially encoding gradient switching including an excitation pulse (1) and a signal acquisition (2) is performed with the MRI system (50), and that the measurement sequence (MS1, MS2) comprises a plurality of measurement blocks (MB1, MB2), each comprising one or more individual measurements (E1, E2) and, during a pause in the spatial encoding, an intermediate gradient (ZW) switched with the MRI system (50), wherein the intermediate gradients (ZW) are dimensioned such that the particle (30) on average over time across each measurement block (MB1, MB2) essentially at the same position (M1,M2). The invention allows for a more reliable and precise determination of the position of a ferromagnetic particle in a liquid matrix.