MRI Gradient Coil Power Prediction With Temperature-Aware Resistance
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Solution Overview
Problem
Conventional magnetic resonance imaging (MRI) systems face challenges in accurately predicting power consumption and voltage drops in gradient magnetic field coils, particularly during high-frequency pulse sequences, leading to potential system shutdowns and the need for time-consuming parameter adjustments and temperature-dependent errors.
Innovation Solution
A magnetic resonance imaging apparatus that includes a gradient magnetic field coil, a power supply with a capacitor, and analysis units to calculate current, power consumption, and voltage values, allowing for precise determination of pulse sequence feasibility by measuring actual resistance and current values, reducing errors and downtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an equivalent circuit model is used to calculate power consumption of gradient magnetic field coils, then power consumption can be predicted, but parameter adjustment takes time and effort and errors occur from actual measured values
Solution Approach 1:
The patent performs preliminary measurements of the gradient magnetic field coil's resistance value and stores it in advance. This pre-measured resistance value is then used in the power consumption calculation formula, eliminating the need for time-consuming parameter adjustments during operation while maintaining high prediction accuracy.
2Measurement precision
If conventional power consumption calculation methods are used, then calculation can be performed, but errors increase with temperature rise of the gradient magnetic field coil
Solution Approach 1:
The patent measures and stores the resistance value of the gradient magnetic field coil at its actual operating temperature rather than using a fixed room temperature value. By using the temperature-dependent resistance value in the power consumption calculation, the method maintains high accuracy even when the coil temperature changes during operation.
3Productivity
If electrolytic capacitor voltage drop is not predicted, then pulse sequences can be executed without pre-checks, but the power supply cannot output target current waveform when voltage drops
Solution Approach 1:
The patent performs preliminary calculation of the electrolytic capacitor voltage drop using the measured resistance value and the intended current waveform before executing the pulse sequence. This pre-check determines whether the capacitor can maintain sufficient voltage, ensuring reliable current waveform output while allowing rapid acceptance or rejection of pulse sequence requests.
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
Accurately determines the feasibility of executing pulse sequences, minimizing system shutdowns and improving imaging efficiency by accounting for frequency-dependent resistance changes and temperature effects.
Implementation Method 1
a gradient magnetic field coil 11 that applies a gradient magnetic field to a subject
Implementation Method 2
a power supply 31 with a capacitor 35 for supplementing power
Implementation Method 3
the resistance value of the gradient magnetic field coil changes also with temperature
Data Source
AI summary
A magnetic resonance imaging apparatus according to exemplary embodiments includes a gradient magnetic field coil, a gradient magnetic field power supply, an analysis unit, a power calculation unit, and a voltage calculation unit. The gradient magnetic field coil applies a gradient magnetic field to a subject. The gradient magnetic field power supply applies a gradient magnetic field current to the gradient magnetic field coil and includes a capacitor for supplementing power therein. The analysis unit calculates, for each frequency, a current value of the gradient magnetic field current to be output to the gradient magnetic field coil in executing a pulse sequence. The power calculation unit calculates power consumption in the gradient magnetic field coil based on a resistance value for each frequency of the gradient magnetic field coil and a current value. The voltage calculation unit calculates a voltage value of the capacitor based on the power consumption.