MRI Sequence Gradient Pulse Adjustment for SAR and Stimulation Limits
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Solution Overview
Problem
Magnetic resonance devices pose safety risks due to high specific absorption rate (SAR) and sudden magnetic field changes, potentially causing patient stimulation and equipment damage, especially for patients with implants.
Innovation Solution
A method to generate a modified magnetic resonance sequence by modifying gradient pulses based on patient-specific boundary conditions, such as maximum magnetic field change rates and gradients, ensuring adherence to safety limits without hardware changes, using a trustworthy component for real-time monitoring and adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high RF energy and strong gradient pulses are used to improve image quality and scan speed, then productivity and image quality improve, but patient safety deteriorates due to excessive SAR and magnetic field stimulation
Solution Approach 1:
The system performs preliminary calculation of SAR and stimulation values based on the original magnetic resonance sequence before execution. This allows prediction of safety parameters in advance, enabling pre-adjustment of the sequence to prevent exceeding safety limits while maintaining scan efficiency
Solution Approach 2:
The system modifies parameters of the magnetic resonance sequence (such as gradient pulse amplitudes, RF pulse powers, and timing) based on calculated safety margins. By dynamically adjusting these parameters, the system maintains optimal imaging performance while ensuring SAR and stimulation values remain within safe boundaries
2Object-affected harmful factors
If conservative safety measures are applied to ensure patient safety, then patient safety improves, but scan performance and productivity deteriorate
Solution Approach 1:
The system automatically calculates safety parameters and adjusts the magnetic resonance sequence without requiring manual intervention or conservative default settings. This self-adjusting mechanism eliminates the need for overly conservative pre-set limits, optimizing scan performance while ensuring safety through real-time parameter adaptation
Solution Approach 2:
The system uses calculated SAR and stimulation values as feedback to iteratively optimize the magnetic resonance sequence. This feedback loop allows the system to identify the maximum safe operating parameters for each specific scan scenario, preventing unnecessary performance reduction while maintaining safety
3Object-affected harmful factors
If gradient pulses are modified to reduce magnetic field change rates for patient safety, then patient safety improves, but image quality and measurement precision deteriorate
Solution Approach 1:
The system selectively modifies gradient pulse parameters (amplitude, duration, slew rate) based on calculated safety margins. By making targeted parameter adjustments only where necessary to meet safety requirements, the system maintains spatial and temporal encoding precision while ensuring magnetic field change rates remain within safe limits
Solution Approach 2:
The system performs preliminary optimization of gradient pulse parameters to achieve the fastest safe ramp rates. This pre-calculation allows the system to use maximum permissible gradient strengths and slew rates throughout the sequence, maintaining image quality while ensuring safety compliance
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
Enhances patient safety by preventing excessive stimulation and equipment damage while maintaining scan performance, allowing safe MR scans for patients with implants.
Implementation Method 1
gradient pulses are switched with the help of a gradient pulse unit. As a result of this, magnetic field gradients are generated in the examination space
Implementation Method 2
radio-frequency (RF) pulses are normally beamed into the patient with the help of a radio-frequency antenna unit. Due to the generated transmission pulses, nuclear spins are excited in the patient
Data Source
AI summary
A method for generating a modified magnetic resonance sequence, a magnetic resonance device, and a computer program product are provided. In accordance with the method, an original magnetic resonance sequence is provided for the acquisition of magnetic resonance signals. The magnetic resonance sequence includes multiple gradient pulses. Further, at least one limit value is provided. At least one modification gradient pulse of the multiple gradient pulses is modified as a function of the at least one limit value, and thus, a modified magnetic resonance sequence is generated.