New Methods

Medical-Imaging Device Developed by NICHD Researchers Awarded U.S. Patent

Device Calibrates MRI Scanners to Improve Image and Data Quality

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The diffusion MRI phantom can be as simple as a hollow plastic sphere, about the size of an adult brain, that contains a substance, polyvinylpyrrolidone (PVP), that can mimic the imaging properties of tissues and organs, such as the brain.

A calibration device for medical imaging developed by researchers at the National Institute of Child Health and Human Development (NICHD) received U.S. Patent approval on March 28, 2017. The device, a diffusion magnetic resonance imaging (MRI) phantom, calibrates MRI scanners that perform diffusion MRI methods, such as diffusion tensor imaging, or DTI. Reliable calibration standards help ensure the quality and accuracy of these images, which can help diagnose stroke, brain disease, and cancer. A patent also can help accelerate the development of promising technology so it can reach health-care providers and patients more quickly.

DTI—invented by NICHD senior investigator Peter Basser and others in 2000—relies on the diffusion of water to generate images and allows researchers to make detailed maps of neural pathways in the brain, as well as of the muscles, heart, and other soft tissues. [link: 

The inventors of the calibration device are Basser, Ferenc Horkay (NICHD), and Carlo Pierpaoli (National Institute of Biomedical Imaging and Bioengineering, formerly of NICHD). The invention uses a substance, polyvinylpyrrolidone, or PVP, to calibrate MRI scanners. PVP is a stable and nontoxic substance used as a food additive.

“We designed the phantom for use in a clinical setting,” said Horkay. “The polymer inside the phantom, PVP, has diffusion properties that can be tailored to match those of the target human tissue.”

DTI visualizes important features of brain anatomy and can aid in the diagnosis of many diseases and disorders of the brain, such as stroke and different cancers. Moreover, DTI data provide neurosurgeons with information about the location of sensitive regions of the brain that they need to avoid during brain surgery.

“We and many other researchers are now evaluating whether DTI can be used to diagnose diseases in which changes in brain tissue structure are subtler, such as mild traumatic brain injury,” said Basser. “In these cases, proper scanner calibration is essential to obtain high-quality, quantitative diffusion MRI measurements.”

The device had been under continuous development and testing by NIH scientists for nearly a decade, and the properties of PVP as a standard for diffusion MRI measurements have been extensively tested by Pierpaoli and collaborators in NICHD. Today, many scientific and clinical research groups use PVP-based diffusion MRI phantoms to ensure data quality, primarily for studies performed across multiple sites.

“This invention will help advance quantitative imaging efforts, which are central to the success of accurate clinical diagnoses, as well as support ongoing clinical studies in which volunteers are imaged at different study sites,” said Pierpaoli.

This article is adapted, with permission, from one that appeared on the NICHD website (

U.S. Patent: F. Horkay, C. Pierpaoli, and P. Basser, Phantom for Diffusion MRI Imaging. Pat. No. 9,603,546, March 28, 2017 (