MRI Gradient Coil Temperature Stabilization via Preheated Cooling
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Solution Overview
Problem
Magnetic resonance imaging (MRI) apparatuses face challenges in maintaining stable temperature of gradient coils during scanning processes due to limited cooling capacity, leading to temperature fluctuations that affect image quality and artifact formation.
Innovation Solution
A magnetic resonance imaging apparatus with a gradient coil cooling system that preheats the metal shims to a predetermined temperature before scanning, using a combination of cooling water temperature control and flow rate adjustments to maintain a constant temperature, thereby stabilizing the gradient coil temperature during imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the flow rate of cooling medium is increased to lower the temperature of the gradient coil, then the temperature control effectiveness is improved, but the cooling pipe diameter must be increased which is limited by structural constraints
Solution Approach 1:
The invention changes the temperature parameter of the cooling medium itself, not just the flow rate. By heating the cooling medium to a higher temperature before it enters the gradient coil, the temperature difference between the cooling medium and the gradient coil is reduced, allowing effective cooling with a lower flow rate and thus maintaining the original cooling pipe diameter.
2Temperature
If the cooling medium temperature is lowered to keep the gradient coil temperature low before scanning, then the initial temperature control is improved, but the gradient coil temperature rises during scanning if the cooling medium temperature remains the same
Solution Approach 1:
The invention performs preliminary heating of the cooling medium to a higher temperature before the scanning process begins. This preliminary action ensures that when scanning starts, the cooling medium is already at the optimal temperature to maintain stable gradient coil temperature throughout the scanning process, avoiding temperature rises that would occur with colder cooling medium.
3Temperature
If conventional cooling is used with limited flow rate, then the cooling system structure is simple, but the temperature changes in gradient coil cannot be inhibited during scanning
Solution Approach 1:
The invention introduces a temperature parameter change to the cooling medium by heating it to a higher temperature before it enters the gradient coil. This parameter change allows the simple cooling system structure to achieve effective temperature stability during scanning, as the heated cooling medium maintains a smaller temperature difference with the gradient coil, improving cooling efficiency without increasing system complexity.
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 inhibits temperature changes in the gradient coil, reducing artifacts and ensuring stable image quality by maintaining the gradient coil temperature at a suitable level for scanning processes.
Implementation Method 1
cooling device for cooling the heat generating sources such as the gradient coil... configured so as to cool the heat generating sources by causing a cooling medium (e.g., water) to circulate through a cooling pipe provided in the surroundings of the heat generating sources
Implementation Method 2
the gradient coil significantly generates heat during scanning processes because a pulsed electric current is repeatedly supplied thereto according to a pulse sequence
Data Source
AI summary
A magnetic resonance imaging apparatus includes; a gradient coil that applies a gradient magnetic field to a static magnetic field in which an examined subject is placed; a metal shim with which the gradient coil is provided and that corrects spatial nonuniformity of the static magnetic field; an executing unit that executes an imaging sequence; and a controlling unit that, before execution of the imaging sequence is started, raises the temperature of the metal shim up to a saturation temperature that is to be reached during the execution of the imaging sequence.