MRI System SAR and Gradient Stimulation Optimization
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Solution Overview
Problem
MRI systems face challenges in achieving optimal image quality while minimizing patient distress and adhering to SAR and gradient stimulation limits, which vary by patient anatomy, leading to conservative settings that result in longer examination times and suboptimal image quality.
Innovation Solution
A method that calculates and simulates the specific absorption rate (SAR) and gradient stimulation for planned measurement sequences, automatically modifying them to ensure compliance with predetermined limits by accounting for individual patient characteristics, using iterative calculations and optimization techniques to generate modified sequences that meet user-defined boundary conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If standardized and rigidly defined threshold values and protocols are used for MRI measurements, then the measurement procedures are simple and efficient, but the SAR and gradient stimulation limits may be exceeded in patients with specific body types or anatomy
Solution Approach 1:
The system performs preliminary calculations of SAR and gradient stimulation values based on patient-specific data (weight, height, body composition) before the actual MRI measurement. This allows the system to predict potential limit exceedances and automatically adjust measurement parameters in advance, ensuring compliance without requiring complex real-time monitoring during the procedure.
Solution Approach 2:
The measurement protocol dynamically adapts its parameters based on calculated patient-specific SAR and gradient stimulation values. The system automatically adjusts measurement parameters such as flip angle, repetition time, and gradient strength to ensure limits are not exceeded, transforming a rigid standardized protocol into a flexible patient-adapted procedure.
2Productivity
If measurement parameters are optimized for minimal acquisition time in normally proportioned patients, then measurement efficiency is maximized, but SAR threshold values may be exceeded in muscular or overweight patients
Solution Approach 1:
The system changes physical parameters of the measurement protocol (flip angle, repetition time, gradient strength, echo time) based on calculated patient-specific SAR and gradient stimulation values. This allows optimization of measurement speed for each patient while maintaining safety limits, rather than using fixed conservative parameters for all patients.
Solution Approach 2:
The system applies patient-specific adjustments to measurement parameters based on individual body characteristics (weight, height, body composition). Each patient receives a tailored measurement protocol that optimizes their specific measurement speed while ensuring their personal safety limits are not exceeded.
3Object-affected harmful factors
If conservative measurement parameters are used to avoid exceeding SAR and gradient stimulation limits, then patient safety is ensured, but measurement times become unnecessarily long and image quality is suboptimal
Solution Approach 1:
The system dynamically adjusts measurement parameters (flip angle, repetition time, gradient strength) based on calculated patient-specific SAR and gradient stimulation values. This replaces conservative fixed parameters with optimized patient-specific parameters that maximize measurement speed while ensuring safety limit compliance.
Solution Approach 2:
The system automatically calculates patient-specific SAR and gradient stimulation values and self-adjusts measurement parameters without requiring manual intervention or conservative default settings. The system serves itself by optimizing its own measurement protocol based on real patient data.
4Reliability
If users manually adjust measurement parameters to comply with SAR and gradient stimulation limits, then limit compliance is achieved, but the adjustment options are very limited and often conflict with diagnostic goals
Solution Approach 1:
The system automatically calculates patient-specific SAR and gradient stimulation values and self-adjusts measurement parameters without requiring manual intervention. This provides extensive adaptability and versatility in parameter adjustment that would be impractical for manual optimization, while ensuring safety limit compliance.
Solution Approach 2:
The system uses calculated SAR and gradient stimulation values as feedback to automatically adjust measurement parameters. This closed-loop approach ensures limit compliance while providing extensive adaptability in parameter optimization, far exceeding what manual adjustment can achieve.
Data Source
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AI summary
The invention relates to a method (7) for operating an MRI system (1) and a corresponding MRI system (1). In the method (7), it is calculated for a planned measurement sequence whether a limit value for a specific absorption rate and/or gradient stimulation is exceeded. If this is the case, the measurement sequence is automatically modified while adhering to a predefined boundary condition. For the modified measurement sequence, it is then calculated again whether the limit values are exceeded. This is repeated iteratively at least until a modified measurement sequence has been automatically generated that does not lead to an exceedance of the limit values and satisfies the predefined boundary condition.