David E J Waddington1,2,3, Mathieu Sarracanie2,3,4, Huiliang Zhang3,5, Torsten Gaebel1, David R Glenn3,5, Ewa Rej1, Najat Salameh2,3,4, Ronald L Walsworth3,5, David J Reilly1, and Matthew S Rosen2,3,4
1School of Physics, University of Sydney, Sydney, Australia, 2A.A Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 3Department of Physics, Harvard University, Cambridge, MA, United States, 4Harvard Medical School, Boston, MA, United States, 5Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, United States
Overhauser-enhanced MRI (OMRI) is a double resonance
technique that has been developed to image free radicals in vivo. Here, we use an
ultra-low field MRI scanner with a highly efficient b-SSFP OMRI protocol to
image synthetic nanodiamonds (NDs) in water at room temperature. Surprisingly, we find that high contrast can
be generated via the Overhauser effect due to paramagnetic impurities in the
ND. Given the already established
application of ND as a biocompatible platform for drug delivery, these results are encouraging for applications based on the non-invasive tracking of nanoparticles using MRI.
