Ambulance MRI Magnet Shielding and Gradient Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current magnetic resonance imaging (MRI) systems are not suitable for emergency ambulance use due to size, weight, power requirements, and safety concerns, and there is a need for a compact, portable, and accessible MRI system that can operate without a power source, providing high signal-to-noise ratio (SNR) for rapid diagnosis of stroke and other conditions in remote areas.
Innovation Solution
A compact, off-grid, hybrid 100 kWh battery-powered MRI system with a mid-field superconducting magnet, high-performance gradients, and advanced RF head coil designs, capable of quick installation and operation in emergency ambulances, using cryogen-free technology and efficient power management to achieve high SNR with reduced magnetic field strength, enabling rapid and safe imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional MRI systems are used, then high diagnostic accuracy is achieved, but the systems are too large and heavy for ambulance transport
Solution Approach 1:
The MRI system is divided into separate modular components including the superconducting magnet, gradient coils, RF system, and control electronics. This segmentation allows each component to be optimized independently and facilitates transport and reconfiguration for mobile ambulance deployment while maintaining diagnostic accuracy through preserved component functionality.
Solution Approach 2:
The patent transitions from traditional horizontal bore magnet configuration to a vertical or compact geometric arrangement. This dimensional reconfiguration reduces the system's footprint and allows the MRI to fit within ambulance constraints while maintaining the necessary magnetic field strength for diagnostic imaging through optimized coil geometry and shielding arrangements.
2Measurement precision
If high magnetic field strength is used to achieve high SNR, then image quality improves, but the system becomes larger and more complex
Solution Approach 1:
The patent employs parameter optimization including using mid-range magnetic field strengths (0.3-0.7T) rather than ultra-high fields, optimizing gradient coil designs for efficiency, and tuning RF pulse sequences to maximize SNR at lower fields. These parameter changes achieve diagnostic-quality imaging while avoiding the complexity and size requirements of high-field systems.
Solution Approach 2:
The system utilizes composite magnetic shielding materials and hybrid coil constructions that combine different materials with complementary properties. This allows achieving the necessary magnetic field homogeneity and shielding effectiveness with reduced overall system complexity compared to traditional single-material approaches.
3Measurement precision
If conventional MRI systems are installed in ambulances, then diagnostic capability is provided, but safety hazards arise from strong magnetic fields attracting metal objects
Solution Approach 1:
The patent actively utilizes the magnetic shielding structure not merely as protection but as a functional component that contains and directs the magnetic field. The shielding materials are configured to channel magnetic flux along predetermined paths, converting what would be hazardous stray fields into controlled field distributions that enhance imaging performance while minimizing external magnetic attraction hazards.
Solution Approach 2:
The system incorporates pre-configured magnetic shielding and field containment structures that are installed before patient loading. These structures proactively prevent metal objects from being attracted to the magnet by establishing controlled magnetic field boundaries, thereby eliminating the projectile hazard before it can manifest during ambulance operation.
4Adaptability or versatility
If MRI systems operate without power sources in remote areas, then accessibility improves, but power availability becomes limited
Solution Approach 1:
The MRI system is designed with multi-functional power capabilities including primary connection to hospital electrical grids for full-performance operation, and secondary capability to operate from alternative power sources such as generators or battery systems for mobile and remote deployments. This universal power adaptability allows the same system to serve both fixed hospital installations and mobile ambulance applications without sacrificing diagnostic capability.
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
The system facilitates early and accurate diagnosis of stroke and other conditions in remote areas, providing high SNR images without the need for a power source, ensuring timely intervention and improving patient outcomes.
Implementation Method 1
mid-field superconducting magnet
Implementation Method 2
magnetic field strength
Implementation Method 3
high-performance gradients
Data Source
AI summary
An ambulance-compatible magnetic resonance imaging (MRI) system for on-site emergency diagnosis includes a mid-field super-conducting head-only magnet including a bore and an active shield arranged relative to the magnet, a passive shield arranged relative to the magnet, the passive shield including a first flange arranged adjacent to a first side of the magnet bore, a second flange arranged adjacent to a second side of the magnet bore, wherein the first flange and the second flange are electrically connected to each other, and wherein the passive shield is operative to capture flux extending out from the magnet bore and return the flux to the magnet. An asymmetric head gradient assembly for generating magnetic gradient field in the mid-field super-conducting magnet is also provided, the magnetic gradient field being between 100-150 mT/m or having a slew rate between 400-800 T/m/s. The MRI system includes a receiver coil and a controller operatively coupled to the receive coil, the controller configured to produce an image based on data obtained from the receive coil. The MRI system is mountable in an ambulance vehicle.