Low-Field MRI With Sparse Sampling for Artifact Control
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Solution Overview
Problem
Conventional magnetic resonance imaging (MRI) systems face challenges in achieving high-quality imaging with minimal magnetic susceptibility and chemical shift artifacts, particularly at low field strengths, while maintaining high frame rates and controlling specific absorption rate (SAR) for real-time diagnostic and interventional applications.
Innovation Solution
The system employs low field strength magnets (≤1.0 Tesla), sparse sampling imaging techniques without parallel imaging, and optimized gradient coil configurations to minimize artifacts and SAR, enabling high frame rate cine MRI with integrated RF coils and control systems that utilize large flip angles and controlled RF bandwidths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If low field strength magnets (≤1.0 Tesla) are used, then magnetic susceptibility artifacts and chemical shift artifacts are reduced, but signal-to-noise ratio deteriorates
Solution Approach 1:
The patent utilizes low magnetic field strength (≤1.0 Tesla) as a parameter change to reduce magnetic susceptibility artifacts and chemical shift artifacts. This parameter modification directly addresses the harmful factors by operating in a lower field regime where these artifacts are inherently reduced, while the system compensates for the lower signal-to-noise ratio through optimized pulse sequences and imaging parameters.
Solution Approach 2:
The system employs dynamic optimization of imaging parameters including variable flip angles, adjusted RF bandwidths, and optimized gradient strengths to maintain adequate signal-to-noise ratio while operating at low field strengths. The control system dynamically adjusts these parameters based on the specific imaging requirements and patient anatomy.
2Productivity
If high frame rates are achieved through fast imaging sequences, then real-time diagnostic capability is improved, but specific absorption rate (SAR) increases
Solution Approach 1:
The patent employs periodic RF pulse sequences with optimized timing parameters to achieve high frame rates while controlling the duty cycle and average power deposition. By carefully designing the repetition time, echo time, and flip angle sequences, the system maintains high temporal resolution while keeping the average SAR within safety limits through periodic rest intervals between excitations.
Solution Approach 2:
The system uses partial Fourier techniques and optimized sampling strategies to achieve high frame rates without requiring full k-space coverage at every time point. This partial action approach reduces the total RF energy required while maintaining sufficient image quality for real-time diagnostic applications.
3Device complexity
If sparse sampling imaging techniques without parallel imaging are used, then system complexity is reduced, but imaging speed and resolution may deteriorate
Solution Approach 1:
The patent implements preliminary optimization of the sparse sampling pattern and reconstruction algorithm parameters before actual imaging. By pre-planning the k-space sampling trajectory and reconstruction strategy, the system achieves efficient data acquisition with reduced complexity while maintaining adequate imaging speed and resolution for the intended applications.
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 achieves high spatial integrity and controlled SAR, allowing for high-quality cine MRI with reduced distortions, suitable for diagnostic and interventional applications, including real-time image-guided surgery and radiotherapy.
Implementation Method 1
a main magnet having a low field strength, a gradient coil assembly, an RF coil system
Implementation Method 2
a strong magnetic field (modified with weak gradient fields applied across it to localize and encode or decode phases and frequencies)
Implementation Method 3
uses the interaction between radio frequency pulses, a strong magnetic field and body tissue to obtain projections, spectral signals, and images
Data Source
AI summary
Improved magnetic resonance imaging systems, methods and software are described including a low field strength main magnet, a gradient coil assembly, an RF coil system, and a control system configured for the acquisition and processing of magnetic resonance imaging data from a patient while utilizing a sparse sampling imaging technique.