Looping Star Multi-Gradient Echo MRI for Acoustic Noise Reduction
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Solution Overview
Problem
Existing magnetic resonance imaging (MRI) techniques produce significant acoustic noise during operation, which can interfere with diagnostic procedures and patient comfort, particularly in functional MRI (fMRI) where brain activity and cognitive function are being evaluated.
Innovation Solution
A silent multi-gradient echo MRI method using a Looping Star acquisition scheme with a closed k-space trajectory that oscillates in and out of a plane, incorporating a 3D radial spatial encoding and auto-calibrated parallel imaging, reducing acoustic noise by minimizing changes in magnetic field gradients and utilizing FID and gradient echo datasets for enhanced image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional MRI techniques are used to acquire images, then image quality and diagnostic information are obtained, but significant acoustic noise is generated during operation
Solution Approach 1:
The patent applies parameter changes by modifying the magnetic field gradient parameters and acquisition timing parameters to reduce acoustic noise. Specifically, it uses variable gradient amplitudes and optimized echo times to minimize noise generation while maintaining image quality through computational methods
Solution Approach 2:
The patent replaces the mechanical acoustic noise generation inherent in conventional MRI with computational image reconstruction methods. By using iterative algorithms and advanced signal processing, the system reconstructs images from reduced-noise data, substituting the mechanical noise problem with a computational solution
2Measurement precision
If magnetic field gradients are used to encode spatial information in MRI, then image resolution is improved, but acoustic noise increases due to gradient switching
Solution Approach 1:
The patent applies dynamics by using variable, time-dependent gradient waveforms rather than static gradient fields. The gradient amplitudes are dynamically adjusted during the acquisition process to optimize both spatial encoding and noise reduction, using adaptive timing and amplitude modulation
Solution Approach 2:
The patent employs periodic gradient switching patterns with optimized timing. By using periodic gradient sequences with specific echo times and repetition rates, the system achieves consistent spatial encoding while minimizing acoustic noise through rhythmic, controlled gradient transitions
3Productivity
If rapid gradient switching is used to improve scan speed, then productivity increases, but acoustic noise and image artifacts worsen
Solution Approach 1:
The patent applies preliminary action by performing computational preprocessing and iterative optimization before final image reconstruction. By pre-calculating correction factors and preparing optimized acquisition parameters in advance, the system achieves rapid scanning without compromising image quality or increasing noise
Solution Approach 2:
The patent implements feedback mechanisms through iterative image reconstruction algorithms that continuously adjust parameters based on acquired data quality. This feedback loop allows the system to maintain high scan speeds while automatically correcting artifacts and optimizing noise reduction in real-time
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 method significantly reduces acoustic noise, enhances image quality by minimizing streaking artifacts and increasing sharpness, and improves spatiotemporal encoding efficiency, making it suitable for diverse MR imaging applications including functional MRI.
Implementation Method 1
When a substance such as human tissue is subjected to a uniform magnetic field (polarizing field B0), the individual magnetic moments of the spins in the tissue attempt to align with this polarizing field, but precess about it in random order at their characteristic Larmor frequency. If the substance, or tissue, is subjected to a magnetic field (excitation field B1) which is in the x-y plane and which is near the Larmor frequency, the net aligned moment, or 'longitudinal magnetization', Mz, may be rotated, or 'tipped', into the x-y plane to produce a net transverse magnetic moment, Mt.
Implementation Method 2
An interconnection of the k-space spokes of the sequence of k-space spokes forms a closed k-space trajectory that refocuses FID signals resulting from the application of the radiofrequency excitation pulse of an initial iteration of the FID acquisition process
Data Source
AI summary
Methods and systems for production of silent, multi-gradient echo, magnetic resonance images includes employing iterative application of small updates to the magnetic field gradient followed by a short, non-selective radiofrequency pulse excitation and for free indication decay data acquisition. The magnetic field gradient updates allow for silent, self-refocusing pulse sequence. Each magnetic field gradient is based in part on a k-space spoke. The multiple spokes, when concatenated, produce a closed k-space trajectory, which results in the self-refocusing pulse sequence. The k-space spokes of the sequence of k-space spokes that forms the closed k-space trajectory oscillate in and out of a plane of a frequency space. Subsequent applications of the magnetic field gradients allow for multiple echo data acquisitions.