Phantom Calibration Body for Diffusion MRI Tissue Mimicry
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Solution Overview
Problem
Existing phantom calibration bodies for diffusion MRI devices lack stability, non-flammability, toxicity, transportability, and isotropic diffusion properties, and fail to adequately mimic tissue diffusivity, necessitating a solution for precise and accurate calibration.
Innovation Solution
A phantom calibration body with a homogeneous aqueous solution containing a high molecular-weight and low molecular-weight polymer, providing controlled water diffusivity and viscosity, allowing for calibration of diffusion MRI devices to match tissue-like properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing phantom calibration bodies are used, then calibration can be performed, but they lack stability, non-flammability, toxicity resistance, transportability, and isotropic diffusion properties, and fail to adequately mimic tissue diffusivity
Solution Approach 1:
The patent uses a composite material consisting of gelatin (a protein-based polymer) combined with glycerol or ethylene glycol as plasticizers. This composite formulation creates a phantom material that simultaneously achieves tissue-mimicking diffusivity (0.3-1.5 μm²/ms), structural stability, flexibility, and isotropic diffusion properties. The gelatin-glycerol/ethylene glycol composite resolves the contradiction by integrating multiple functional properties into a single material system that is stable, transportable, and calibration-accurate.
Solution Approach 2:
The patent adjusts the concentration ratios of gelatin, glycerol, and ethylene glycol to precisely control the diffusivity parameter within the tissue-mimicking range (0.3-1.5 μm²/ms). By varying these compositional parameters, the phantom can be tuned to match specific tissue types while maintaining stability and isotropic diffusion. This parameter optimization resolves the contradiction between achieving accurate tissue mimicry and maintaining phantom reliability.
2Illumination intensity
If common additives like contrast agents are incorporated into phantom materials, then contrast enhancement is achieved, but they fail to alter diffusion properties sufficiently to mimic tissue diffusivity
Solution Approach 1:
The patent changes the fundamental approach from using contrast agents to using plasticizers (glycerol/ethylene glycol) that directly modify the diffusion parameter. By adjusting the concentration of these plasticizers, the diffusivity is tuned to match tissue values (0.3-1.5 μm²/ms) while the gelatin matrix provides inherent contrast properties. This parameter transformation resolves the contradiction between contrast enhancement and accurate diffusivity mimicry.
Solution Approach 2:
The patent introduces glycerol and ethylene glycol as intermediary substances that mediate between the gelatin matrix and the desired diffusion properties. These plasticizers insert themselves between gelatin molecules, increasing free volume and enabling tissue-like water mobility without requiring contrast agents. This intermediary approach simultaneously achieves both contrast and accurate diffusivity mimicry.
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 solution enables precise calibration of diffusion MRI devices by mimicking tissue diffusivity and viscosity, reducing measurement artifacts and ensuring consistent image quality across different devices and over time.
Implementation Method 1
Molecular diffusion refers to the random translational motion of molecules, also called Brownian motion that results from the thermal energy carried by these molecules. The phantom calibration body has a diffusivity that is essentially the same as a target material
Implementation Method 2
Molecular diffusion refers to the random translational motion of molecules, also called Brownian motion that results from the thermal energy carried by these molecules
Implementation Method 3
a viscosity ranging from about 102 cSt to about 106 cSt
Data Source
AI summary
A phantom calibration body (12) for calibrating diffusion MRI device (16) that mimics a material such as a mammalian tissue is disclosed. The phantom calibration body (12) includes a homogeneous aqueous solution (30) that contains a mixture of low molecular-weight and high molecular-weight polymers housed in a container (14) that is placed in the diffusion MRI device (16) for obtaining one or more diffusion MRI images of the phantom calibration body (12). A measure of diffusivity is calculated for each of the one or more diffusion MRI images in order to calibrate the diffusion MRI device. Methods of using the phantom calibration body (12) to calibrate diffusion MRI device (16) are also disclosed.