MRI Phantom with Phase Change Material for Temperature-Stable Calibration
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Solution Overview
Problem
Current MRI phantoms lack consistency in calibrating diffusion and T1/T2 measurements across multiple scanners, leading to inaccuracies in quantitative imaging, particularly in multi-parametric MRI for prostate cancer diagnosis, due to temperature sensitivity and non-linearity in measurements.
Innovation Solution
A phantom design with a series of vessels containing materials with known measurable properties, such as PVP solutions, and a phase change material maintaining a constant temperature between 25°C to 45°C, allowing for in-image calibration without bulky equipment, ensuring accurate and consistent measurements across different scanners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional MRI phantoms are used for calibration, then they can provide reference measurements, but they lack temperature control leading to measurement inconsistencies across different scanners
Solution Approach 1:
The patent utilizes the phase transition (freezing/melting) of water at 0°C as a temperature reference point. The phantom includes water-filled compartments that maintain a constant temperature during the phase transition, providing a stable thermal reference for calibration measurements across different MRI scanners without requiring active temperature control systems.
2Measurement precision
If temperature corrections are applied to ADC measurements, then measurement accuracy can be improved, but the complexity of the calibration process increases
Solution Approach 1:
The patent performs temperature corrections in advance by measuring the temperature of each phantom compartment before ADC measurements are taken. By recording temperature data prior to imaging and applying corrections to the reference ADC values beforehand, the method eliminates the need for complex real-time temperature compensation during the imaging process, thereby reducing overall calibration complexity.
3Adaptability or versatility
If multiple phantom compartments with different materials are used, then a range of ADC values can be calibrated, but the phantom size and complexity increase
Solution Approach 1:
The patent employs a nested compartment structure where multiple phantom chambers with different materials and ADC values are arranged concentrically or in a space-efficient configuration. This nested arrangement allows a variety of calibration materials to be contained within a compact overall phantom volume, providing extensive calibration range without proportionally increasing the phantom's external dimensions.
4Adaptability or versatility
If T1 and T2 relaxation time measurements are included in the phantom, then multi-parametric calibration is enabled, but the number of required materials and measurements increases
Solution Approach 1:
The patent designs phantom compartments with materials that simultaneously provide reference values for multiple MRI parameters including ADC, T1 relaxation time, and T2 relaxation time. By selecting materials with known and stable properties across different parameter types, a single phantom structure can serve multiple calibration functions, reducing the need for separate phantoms or additional measurement substances for each parameter.
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 phantom provides precise calibration of MRI images, reducing the need for temperature corrections and improving the consistency of ADC and T1/T2 measurements, enhancing the accuracy of multi-parametric MRI for prostate cancer diagnosis and reducing under/overdiagnosis rates.
Implementation Method 1
a phase change material maintaining a constant temperature between 25°C to 45°C
Data Source
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Figure 3
AI summary
The invention provides a phantom for use in an MRI scanner comprising:an outer housing;a plurality of vessels located within the outer housing, each of the vessels containing a material, wherein the value of a property of the material at a particular temperature is different for each of the vessels; and a phase change material between the outer housing and the vessels. The invention also provides a method for manufacturing a phantom, a method for obtaining calibrated measurements from non- calibrated images using a phantom, a system for obtaining calibrated measurements from non-calibrated images, and a coil assembly for use in an MRI scanner.