Gradient Pulse Optimization for MRI Eddy Current Reduction
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Solution Overview
Problem
Magnetic resonance tomography devices face challenges with high slew rates and gradient amplitudes leading to eddy currents, noise, and peripheral nerve stimulation, which compromise image quality and increase energy consumption.
Innovation Solution
A method and device that optimize gradient-pulse parameters within specified intra-repetition-interval time parameters to minimize eddy currents and noise while maintaining image quality, using a sequence calculator to adjust slew rate and gradient amplitude, reducing energy consumption and peripheral nerve stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high slew rates and high gradient amplitudes are used, then imaging efficiency and speed are improved, but eddy currents increase causing noise and peripheral nerve stimulation
Solution Approach 1:
The patent optimizes gradient-pulse parameters (slew rate and gradient amplitude) by adjusting timing parameters within the repetition interval. The sequence calculator modifies the timing of gradient pulses to reduce peak values while maintaining the same measurement time and image quality, thereby reducing eddy currents without sacrificing imaging speed
Solution Approach 2:
The patent dynamically adjusts gradient-pulse parameters based on timing optimization within the repetition interval. By making the gradient pulse timing adaptive and flexible within the constrained measurement time, the system achieves reduced peak gradient values and slew rates while maintaining imaging efficiency
2Productivity
If high slew rates and high gradient amplitudes are used, then imaging efficiency is improved, but noise increases
Solution Approach 1:
The patent reduces noise by optimizing the timing of gradient pulses within the repetition interval, which reduces peak gradient amplitudes and slew rates. This parameter optimization maintains imaging efficiency while significantly reducing noise generation from gradient switching
Solution Approach 2:
The patent converts the constraint of fixed measurement time into a benefit by optimizing the distribution of gradient pulses within that time. The optimization reduces peak gradient values and associated noise while maintaining the same total measurement duration, effectively using the time constraint to achieve quieter operation
3Productivity
If high slew rates and high gradient amplitudes are used, then imaging efficiency is improved, but energy consumption increases
Solution Approach 1:
The patent reduces energy consumption by optimizing gradient-pulse parameters through timing adjustments within the repetition interval. By reducing peak gradient amplitudes and slew rates while maintaining the same measurement time, the system achieves lower energy consumption without sacrificing imaging efficiency
4Productivity
If high slew rates and high gradient amplitudes are used, then imaging efficiency is improved, but peripheral nerve stimulation increases
Solution Approach 1:
The patent reduces peripheral nerve stimulation by optimizing the timing of gradient pulses within the repetition interval, which reduces peak gradient amplitudes and slew rates. This optimization maintains imaging efficiency while reducing the intensity of gradient switching that causes peripheral nerve stimulation
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
Significantly reduces noise and peripheral nerve stimulation without degrading image quality, achieving noise reduction of up to 10 dBA in spin-echo sequences and lowering energy consumption.
Implementation Method 1
A magnetic field gradient is also applied with the aid of a gradient system
Implementation Method 2
High-frequency excitation signals (HF signals) are emitted by suitable antenna devices via a high-frequency transmission system, which is intended to cause the nuclear spins of specific atoms that have been excited in a resonant manner
Implementation Method 3
the induction of eddy currents by the gradient pulses into surrounding metallic surfaces (e.g., the high-frequency screen of the magnetic resonance tomography device or even into the body of a patient or test subject)
Data Source
AI summary
A method and a measuring-sequence-determining device for determining a measuring sequence for a magnetic resonance system based on at least one intra-repetition-interval time parameter are provided. During the determination of the measuring sequence in a gradient-optimization method, gradient-pulse parameters of the measuring sequence are automatically optimized to reduce at least one gradient-pulse-parameter maximum value. As a boundary condition in the gradient-optimization method, the intra-repetition-interval time parameter is kept constant at least within a specified tolerance value.