Vibrating MRI Magnet Components for Gradient Control
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Solution Overview
Problem
Conventional MRI systems using one-sided magnets struggle to efficiently encode in-plane information due to fixed gradient velocities and directions, limiting the ability to control k-space velocity and gradient synchronization with pulse sequences, which results in incomplete data sampling and reduced image acquisition speed.
Innovation Solution
The use of electromechanical actuators to dynamically modify the shape or position of magnet components, allowing for controlled translational, tilting, or rotational movements to adjust the magnetic field gradients in real-time, enabling synchronized in-plane k-space velocity control and gradient variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If dedicated gradient coils with high current are used to achieve high gradient field strength, then data entry speed into k-space is improved, but device complexity and power dissipation increase significantly
Solution Approach 1:
The patent combines the gradient field generation function with the basic field magnet by using electromechanical actuators to move magnet components, eliminating the need for separate gradient coils and their associated high-current amplifiers, thereby reducing device complexity while maintaining data acquisition speed
Solution Approach 2:
The patent replaces the electrical gradient coil system with a mechanical system consisting of electromechanical actuators that physically move magnet components to generate gradient fields, substituting high-current electrical systems with mechanical positioning systems
2Device complexity
If the basic field magnet is used to generate both basic field and gradient fields, then device complexity is reduced, but the ability to control in-plane k-space velocity and synchronize gradients with pulse sequences is limited
Solution Approach 1:
The patent divides the basic field magnet into separable components, with at least one component mounted on electromechanical actuators that can be independently positioned, allowing different segments to be controlled differently to achieve both gradient generation and k-space velocity control
Solution Approach 2:
The patent introduces dynamic control by enabling electromechanical actuators to adjust the position and orientation of magnet components in real-time, allowing the gradient fields to be dynamically modulated to match pulse sequence requirements and control in-plane k-space velocity
3Productivity
If static gradient fields are used from the one-sided magnet, then image acquisition can be performed, but the scanning speed and data sampling density are insufficient due to fixed gradient velocities
Solution Approach 1:
The patent transforms static gradient fields into dynamic gradient fields by using electromechanical actuators to move magnet components during the imaging process, enabling variable k-space scanning speeds and improved data sampling density without requiring separate gradient coils
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 faster image acquisition by modifying the magnet configuration within the spin relaxation times, enabling efficient encoding of in-plane information and increased data sampling density, thereby reducing patient scanning time.
Implementation Method 1
a magnetic resonance imaging apparatus operates by placing the examination subject in a strong and highly uniform basic magnetic field, having a field strength of up to several Tesla or more. This strong basic magnetic field causes nuclei in the examination subject to become oriented along the field lines of the basic magnetic field.
Implementation Method 2
Radio-frequency (RF) energy, usually in the form of RF pulses, is radiated into the examination subject. The RF energy causes certain nuclei (nuclear spins) in the subject to resonate. The nuclei spins are given a magnetization dependent on attributes of the RF energy, so that these nuclear spins are deflected from the steady state or equilibrium position by an amount known as the flip angle, and as these excited nuclear spins relax and return to the steady state, they emit RF signals, called magnetic resonance (MR) signals.
Implementation Method 3
In order to identify the point of origin of each detected MR signal, magnetic field gradients are produced during the aforementioned procedure, which spatially encode the MR signals.
Implementation Method 4
The use of electromechanical actuators to dynamically modify the shape or position of magnet components, allowing for controlled translational, tilting, or rotational movements to adjust the magnetic field gradients in real-time
Data Source
AI summary
A magnet assembly for magnetic resonance imaging is used to generate the basic magnetic field with a strength needed to produce the steady state or equilibrium position of nuclei or nuclear spins in magnetic resonance imaging. This magnet, or a part thereof, is vibrated or tilted or otherwise periodically moved so as to change its position and thereby generate a time-varying gradient field, which is used to enter the acquired magnetic resonance signals as raw data into k-space.