WARF: P110135US01

Method for Quantification of R2 Relaxivity in Magnetic Resonance Imaging


Scott Reeder, Diego Hernando Arribas

The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing a method for measuring transverse relaxation rate (R2*) corrected for confounding factors.
OVERVIEWMapping of effective transverse relaxation rate (R2*) relaxivity has important applications in magnetic resonance imaging (MRI) including blood oxygenation level dependent functional imaging, detection and tracking of superparamagnetic iron oxides and assessment of iron content in the brain, heart, pancreas and liver. Measurement of hepatic iron content (HIC) is important for detection and quantification of iron overload. R2* has been shown to be strongly correlated to HIC.

Mapping of R2* in MRI can be performed from a set of gradient echo images acquired with different echo times. Measurements of R2* are affected by several confounding factors. These confounding factors generally make R2* maps dependent on the data acquisition parameters and may lead to misdiagnosis. A method for accurate measurement of R2* is needed that corrects confounding factors and is independent of data acquisition parameters and specific MRI system hardware.
THE INVENTIONUW–Madison researchers have developed a method for measuring R2* with MRI in which signal decays that occur as a result of macroscopic variations in the main magnetic field of the MRI system are incorporated into a chemical-shift based signal model. The model provides for the mitigation of errors due to macroscopic field variations and allows better signal-to-noise ratio performance compared to existing R2* measurements.

The method samples echo signals occurring at different echo times to acquire MRI image data. For each of the echo signals, a signal model is formed to account for relative signal components for each different chemical species, such as water and fat. Magnetic field inhomogeneity values associated with the MRI system are estimated by fitting the acquired image data to the signal models. This allows the creation of signal models that account for relative signal components for each different chemical species and signal decay resulting from macroscopic variations in the main magnetic field of the MRI system. The method also allows estimation of R2* for at least one of the chemical species by fitting the acquired image data to the signal models.
  • Diagnostic MRI including non-invasive assessment of hepatic and cardiac iron
  • Allows accurate quantification of R2* relaxivity
  • Accounts for confounding factors
  • Improves signal-to-noise performance
For More Information About the Inventors
  • Hines et al. 2011. T(1) Independent, T(2) (*) Corrected Chemical Shift Based Fat-Water Separation with Multi-Peak Fat Spectral Modeling Is an Accurate and Precise Measure of Hepatic Steatosis. J Magn Reson Imaging. 33, 873-881.
  • Hernando D., Vigen K.K., Shimakawa A. and Reeder S.B. 2012. R2* Mapping in the Presence of Macroscopic B0 Field Variations. Magn Reson Med. 68, 830-840.
Tech Fields
Contact Information
For current licensing status, please contact Jeanine Burmania at or 608-960-9846.
The WARF Advantage

Since its founding in 1925 as the patenting and licensing organization for the University of Wisconsin-Madison, WARF has been working with business and industry to transform university research into products that benefit society. WARF intellectual property managers and licensing staff members are leaders in the field of university-based technology transfer. They are familiar with the intricacies of patenting, have worked with researchers in relevant disciplines, understand industries and markets, and have negotiated innovative licensing strategies to meet the individual needs of business clients.