Phantom for diffusion MRI imaging
Inventors
Horkay, Ferenc • Pierpaoli, Carlo • Basser, Peter J.
Assignees
US Department of Health and Human Services
Publication Number
US-9603546-B2
Publication Date
2017-03-28
Expiration Date
2030-01-26
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
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.
Core Innovation
The invention relates to a phantom calibration body and methods of using it to calibrate diffusion MRI devices. The phantom calibration body comprises a homogeneous aqueous solution containing a mixture of low molecular-weight and high molecular-weight polymers formulated to provide a specified water diffusivity and viscosity. This aqueous solution mimics the diffusion properties of a target material, such as mammalian tissue, and is housed within a container suitable for use in diffusion MRI devices.
The problem addressed is the need for precise, accurate, and repeatable diffusion MRI data, which can vary between devices and over time due to hardware changes or software updates. Existing phantom calibration bodies do not adequately provide stability, safety (non-flammability, non-toxicity), transportability, vibration damping, or isotropic diffusion properties within a useful range of viscosities. Additionally, previous additives have failed to sufficiently mimic tissue diffusivity. This invention seeks to provide a phantom calibration body with known and controllable water diffusivity characteristics that match those of tissues for calibration, alongside methods for manufacturing and using such phantom calibration bodies.
Claims Coverage
The patent includes two main independent claims covering methods for calibrating diffusion MRI devices using a phantom calibration body with specific polymer composition and physical properties, and a method for calibrating resolution aspects of the device.
Method for calibrating diffusion MRI device with polymer phantom
A method of calibrating a diffusion MRI device by providing a phantom calibration body comprising a homogeneous aqueous solution of polyvinyl pyrrolidone with a molecular weight distribution mean of 5-1000 kDa; the solution having diffusivity essentially the same as a target mammalian tissue and viscosity ranging from about 102 to 106 centistokes. The method includes placing the phantom in the MRI device, obtaining diffusion imaging data, calculating a diffusivity measurement indicative of water diffusivity, and calibrating the device based on the measurement.
Method for calibrating resolution performance parameter using known phantom dimensions
A method of calibrating resolution performance parameters (image resolution and distortion) of a diffusion MRI device by providing a phantom calibration body with known dimensions containing a homogeneous aqueous solution of polyvinyl pyrrolidone with molecular weight distribution mean of 5-1000 kDa, and diffusivity and viscosity within specified ranges. The method includes placing the phantom in the device, obtaining diffusion-weighted images, extracting image dimensions, comparing these to known phantom dimensions, determining the resolution performance parameter, and calibrating the device accordingly.
The claims provide inventive coverage of methods for calibrating diffusion MRI devices using a phantom calibration body composed of polyvinyl pyrrolidone polymers with specified molecular weight distributions, diffusivity, and viscosity. The claims address both diffusion measurement calibration and resolution calibration, highlighting specification of polymer composition, imaging data acquisition, and calibration based on calculated measurements and comparisons to known phantom properties.
Stated Advantages
The phantom calibration body is stable, non-flammable, non-toxic, transportable, and vibration damping.
It exhibits isotropic diffusion properties within a wide range of viscosities.
The solution’s diffusivity can be matched to that of target mammalian tissues, improving calibration accuracy.
The container shape (e.g., spherical) minimizes susceptibility artifacts during imaging.
The phantom facilitates routine calibration, quality assurance, and manufacturing assessment of diffusion MRI devices.
Documented Applications
Routine maintenance and calibration of institutional diffusion MRI devices in radiology departments, hospitals, and clinics.
Quality assurance and quality control processes by vendors during manufacturing, installation, repair, or performance assessment of diffusion MRI devices.
Calibration and standardization across multiple diffusion MRI devices or institutions.
Assessment and calibration of diffusion MRI device prototypes and design refinement during development.
Calibration of spatial resolution and image distortion using the container’s known dimensions as a resolution phantom.
Validation and benchmarking of diffusion tensor imaging (DTI) measurements, including characterization of isotropic, anisotropic, and non-Gaussian diffusion.
Calibration of advanced diffusion MRI techniques such as Q-ball imaging, diffusion spectrum imaging, and multiple pulsed-field gradient methods.
Interested in licensing this patent?