The phantom provided in this invention comprises a stable aqueous solution with a concentration of at least 30%, by weight, of a mixture of a high molecular-weight polymer or copolymer and a low molecular-weight polymer or copolymer, the aqueous solution having a resulting water diffusivity from about 2x10-4 mm2/s to about 3x10-3 mm2/s. Polyvinyl Pyrrolidone (PVP) is the polymer of choice used in this invention. The phantoms of this invention are uniquely stable, non-toxic, and transportable, and have shown to maintain constant water diffusivity after two years.

Advantages:

The imaging phantoms provided in the invention are optimized specifically for Diffusion MRI. They possess the following features and characteristics:

• Made of non-toxic, non-hazardous, non-flammable and easily transportable materials.

• Possess diffusivities similar to those of water in biological tissues, particular brain parenchyma

• Possess stable diffusion properties over time. No appreciable change in water diffusivity was detectable after two years.

• Offers option to tailor diffusiveness of the phantoms to different applications by varying the ratios of the chemical components.

In addition, the inventors established a procedure to make concentrated solutions (up to 80 wt% polymer content) from mixtures of different molecular weight polyvinyl pyrrolidone (PVP) polymer and/or vinylpyrrolidone-based copolymers in water in the presence of physiologically relevant ions and gadolinium-based MRI contrast agents. In general, preparation of homogeneous polymer solutions from hydrophilic glassy polymers with high solute content is problematic due to the inter- and intra-molecular interactions (e.g., hydrogen bonds) leading to formation of entanglements and gelation. This discovery indicates that at certain PVP-water compositions the new preparation procedure gives rise to disengagement of polymer chains and considerably improves polymer solubility. Moreover, the addition of lower molecular weight PVP and/or vinylpyrrolidone-based copolymers decreases the intra molecular association among the polymer molecules without significantly affecting the diffusive and relaxation properties of the solvent (water) in the MRI phantom.

Development Status:

The invention is fully developed.

Market:

• The market for medical imaging equipment industry is approximately $9.0 billion dollars now and has been growing by approximately 7.6% annually. MRI instrumentation constitutes a significant portion of this market.

• Diffusion MRI is now a mature technology that has received FDA approval; Diffusion MRI methods are "made, used and sold" by all major MRI manufacturers. The installed base of clinical scanners using Diffusion MRI methods, including DTI, must now be in the thousands, worldwide.

• Imaging phantoms are necessary component of any imaging system as they provide the means for the systems’ standardization and quality control, and are thus a required component for their reliable performance. Commercial success of these phantoms described in the invention is therefore expected, in particular in view of the unique characteristics possessed by these phantoms as outlined above. Due to these properties they can be stored in a medical facility without special permits or requirements.

• The phantoms described in this invention could be sold with new MRI scanners supporting DTI and other diffusion MRI methods or for existing MRI scanners that support diffusion MRI applications. These phantoms could be used by MRI companies internally for product sequence testing and development as well as to ensure that MRI scanners shipped to users operate work properly and to within "specs" following installation. The phantoms should be of interest to medical physicists, technicians and bioengineers charged with the responsibility of assuring quality and reproducibility in their routine and research scans.

Collaborative Research Opportunity: The Eunice Kennedy Shriver National Institute of Child Health and Human Development’s Section on Tissue Biophysics & Biomimetics (STBB) is seeking statements of capability or interest from outside parties who are interested in entering into a Collaborative Research and Development Agreement (CRADA) to develop and commercialize the Diffusion MRI Phantom described above. Please contact Alan Hubbs, Ph.D. at 301-594-4263 or hubbsa@mail.nih.gov for more information.