MRI Gradient Coil Temperature Control via Preliminary Estimation
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Solution Overview
Problem
Conventional MRI apparatuses face issues with temperature fluctuations in gradient coils, leading to image artifacts and prolonged examination times due to delayed temperature control and inefficient temperature stabilization of metal shims.
Innovation Solution
The MRI apparatus employs a processing circuitry to estimate and control the temperature of the gradient coil, using a cooling system that adjusts the temperature of cooling water flowing into and out of the coil, ensuring the gradient coil and metal shim temperatures are stabilized in real-time, thereby maintaining a consistent center frequency for RF pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If cooling water temperature control is implemented by measuring outlet temperature and adjusting inlet temperature, then temperature stabilization is achieved, but there is a time delay that prevents real-time control
Solution Approach 1:
The system estimates the temperature of the gradient coil in advance before actual temperature deviation occurs, and pre-adjusts the cooling water temperature accordingly. This preliminary action eliminates the time delay inherent in conventional feedback control that waits to measure outlet temperature before making adjustments.
Solution Approach 2:
The system implements a feedback mechanism where the estimated temperature information is continuously used to adjust the cooling water temperature, creating a closed-loop control system that actively maintains gradient coil temperature stability rather than merely reacting to temperature changes.
2Measurement precision
If conventional cooling control is used with outlet temperature measurement, then temperature monitoring is achieved, but examination time is prolonged due to delayed temperature control
Solution Approach 1:
By estimating the gradient coil temperature in advance and adjusting cooling water temperature proactively, the system prevents temperature fluctuations before they affect image quality, eliminating the need for repeated temperature stabilization cycles that prolong examination time.
Solution Approach 2:
The system replaces direct physical temperature measurement with an estimation mechanism that uses operational parameters to calculate temperature, enabling faster and more frequent temperature assessments without the time-consuming delays of physical sensing and reaction.
3Device complexity
If gradient coil temperature fluctuates, then cooling control is simplified, but image quality deteriorates due to center frequency drift
Solution Approach 1:
The system proactively estimates temperature and adjusts cooling water before temperature fluctuations can cause center frequency drift, preventing image quality deterioration while maintaining relatively simple control logic based on operational parameters.
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
This approach effectively suppresses temperature fluctuations, improving image quality and reducing examination time by ensuring precise temperature control of the gradient coil and metal shim, thus enhancing the accuracy and efficiency of MRI scans.
Implementation Method 1
a cooling system 200 that cools the gradient coil 2 by causing cooling water to flow into and out of the gradient coil 2
Implementation Method 2
a gradient coil 2 that generates a gradient magnetic field in an imaging space in which a subject is placed
Data Source
AI summary
A magnetic-resonance imaging apparatus of an embodiment includes a gradient coil, a transmitter coil, and a processing circuitry. The gradient coil applies a gradient magnetic field to an imaging space in which a subject is placed. The transmitter coil applies a RF (radio frequency) pulse to the imaging space. The processing circuitry calculates a target temperature of the gradient coil throughout multiple protocols to be executed in an examination of the subject, and controls a temperature of the gradient coil to approach the target temperature when a data used to set a center frequency of the RF pulse is measured.