MRI Phantom Variable Volume Reservoir for Thermal Expansion
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Solution Overview
Problem
MRI geometric distortion phantoms face accuracy issues due to pressure changes caused by thermal expansion mismatches between materials, leading to potential structural integrity problems and image distortion, especially in image-guided applications where precision is critical.
Innovation Solution
A MRI quality assurance device with a housing made of rigid, MRI-invisible material containing sealed reservoirs with a first non-expandable volume portion and a second variable volume portion, allowing for fluid communication and accommodating volume changes, thereby maintaining geometric accuracy and structural integrity under temperature and pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sealed MRI phantom container is used to maintain geometric accuracy, then measurement precision is improved, but pressure changes from thermal expansion cause structural integrity problems and potential rupture
Solution Approach 1:
The patent introduces a flexible membrane or balloon structure that can expand and contract in response to pressure changes from thermal expansion. This flexible element absorbs the stress that would otherwise cause rupture, while the rigid outer housing maintains the overall geometric accuracy needed for MRI measurements. The flexible membrane acts as a pressure relief mechanism that preserves both structural integrity and measurement precision.
2Reliability
If the MRI phantom is sealed to prevent leakage, then reliability is improved, but thermal expansion pressure causes geometric distortion
Solution Approach 1:
The flexible membrane serves as an internal pressure accommodation mechanism that allows the sealed container to expand slightly without causing geometric distortion of the overall phantom structure. This maintains both the leak-proof seal and the geometric accuracy required for precise MRI measurements.
3Manufacturing precision
If a rigid container is used to maintain phantom geometry, then manufacturing precision is improved, but thermal expansion pressure causes structural failure
Solution Approach 1:
The combination of rigid outer housing and flexible internal membrane creates a composite structure where the rigid portion maintains geometric accuracy and the flexible portion absorbs pressure stresses. This resolves the contradiction by distributing the thermal expansion forces to the flexible element rather than allowing them to cause structural failure of the rigid container.
4Adaptability or versatility
If the MRI phantom is subjected to temperature fluctuations during shipping, then adaptability is improved, but pressure changes cause liquid rupture from the phantom
Solution Approach 1:
The flexible membrane or balloon structure acts as a shock absorber for thermal expansion forces during shipping. When temperature fluctuations cause pressure changes, the flexible element expands or contracts accordingly, preventing the liquid from rupturing through the container walls. This enables the phantom to withstand temperature variations while maintaining leak prevention.
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
The device effectively maintains geometric accuracy and prevents rupture or leaks, ensuring precise measurements and reliable performance even under varying environmental conditions, such as during shipping.
Implementation Method 1
the change in pressure per degree Celsius (ΔP/° C.) is about 60 kPa/° C. This is a significant increase in the internal pressure of a sealed vessel, such as a MRI phantom
Data Source
AI summary
A MRI quality assurance device, according to the present invention, has a housing made of a rigid MRI invisible material containing one or more sealed reservoirs containing a fluid MRI signal producing material. Each sealed reservoir has a first volume portion and a second variable volume portion in fluid communication therewith.