Unshielded Gradient Coils in Zero Echo Time MRI Systems
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Solution Overview
Problem
Conventional magnetic resonance imaging (MRI) systems are expensive and complex, requiring shielded gradient coils for accurate imaging, which limits their availability and increases radiation exposure, especially in developing countries where X-rays are frequently used for diagnosing conditions like tuberculosis, and they are not suitable for rapid, low-cost imaging of large areas or specific tissues like bones and lungs.
Innovation Solution
A magnetic resonance imaging system utilizing unshielded gradient coils with a zero echo time pulse sequence for acquiring volumetric data, allowing for inexpensive construction and simultaneous imaging of hard tissues with good diagnostic quality, and enabling the projection of three-dimensional images onto two-dimensional planes for reduced radiation exposure and simplified operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI systems with shielded gradient coils are used, then imaging accuracy is improved, but system cost and complexity increase
Solution Approach 1:
The patent removes the gradient coil shielding structure from the MRI system, extracting only the essential gradient coil functionality while eliminating the complex shielding components. This reduction in system complexity lowers cost and improves accessibility while maintaining sufficient imaging accuracy for clinical applications through optimized pulse sequences and gradient parameters.
Solution Approach 2:
The patent employs optimized pulse sequence parameters and gradient waveforms to compensate for the reduced performance of unshielded gradient coils. By adjusting parameters such as gradient amplitude, duration, and timing, the system maintains imaging accuracy despite the simplified coil structure, resolving the contradiction between simplicity and precision.
2Measurement precision
If X-rays are used for diagnosing tuberculosis, then diagnostic capability is improved, but radiation exposure increases
Solution Approach 1:
The patent replaces the X-ray imaging mechanism with an MRI mechanism using unshielded gradient coils and optimized pulse sequences. This substitution eliminates ionizing radiation while providing comparable or superior soft tissue contrast for diagnosing tuberculosis and other pulmonary conditions, removing the harmful radiation effect while preserving diagnostic capability.
3Measurement precision
If shielded gradient coils are used, then imaging quality is improved, but availability and accessibility decrease
Solution Approach 1:
The patent adopts a simplified unshielded gradient coil design that is cheaper to manufacture and maintain, making MRI systems more accessible in resource-limited settings. While the coils have shorter operational lifespan compared to shielded versions, the reduced cost enables broader deployment and availability, particularly in developing countries where tuberculosis diagnosis is critical.
4Measurement precision
If conventional MRI sequences are used, then detailed tissue imaging is improved, but imaging time increases
Solution Approach 1:
The patent employs periodic pulse sequences with optimized timing and repetition rates to acquire sufficient tissue detail within reduced timeframes. By using repeated excitations with appropriate echo times and signal averaging, the system maintains imaging quality while minimizing total scan duration, addressing the time-quality trade-off.
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 provides cost-effective, efficient, and radiation-reduced imaging capabilities, suitable for diagnosing conditions like tuberculosis and bone disorders, with simplified operation and the ability to image large areas or specific tissues like lungs, while maintaining good signal-to-noise ratio and diagnostic quality.
Implementation Method 1
a magnet for generating a main magnetic field with an imaging zone
Implementation Method 2
a gradient coil system for generating a gradient magnetic field within the imaging zone
Implementation Method 3
recording magnetic resonance signals of an object to be examined by way of the magnetic resonance sequence
Data Source
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AI summary
The invention provides for a magnetic resonance imaging system (100) comprising: a magnet (104) for generating a main magnetic field with an imaging zone (110), and a gradient coil system (110, 112). The gradient coil system comprises a set of unshielded gradient coils (110). The magnetic resonance imaging system further comprises a processor (130) for controlling the magnetic resonance imaging system. Execution of the instructions stored in a memory cause the processor to: acquire (200, 304) imaging magnetic resonance data (152) from a volume (109) within the imaging zone using a zero echo time pulse sequence; reconstruct (202, 306) a three-dimensional image (156) using the imaging magnetic resonance data; subtract a calibration image from the three-dimensional image, the calibration image having been acquired without a subject in the imaging zone; and render the three-dimensional image on a display by projecting it on a two-dimensional plane.