Luca Frullano1, Ciprian Catana1,
Thomas Benner1, A. Dean Sherry2,3, Peter Caravan1,4
1A. A. Martinos Center for Biomedical
Imaging, Massachusetts General Hospital, Charlestown, MA, United States; 2Chemistry,
University of Texas at Dallas, Dallas, TX, United States; 3Advanced
Imaging Research Center, UT Southwestern, Dallas, TX, United States; 4Radiology,
Harvard Medical School, Charlestown, MA, United States
In
vivo application of activatable contrast agents is limited by the inability
to determine both probe concentration and relaxivity. One approach to this problem is
simultaneous MR-PET using a dual MR-PET probe, where PET provides
quantification of probe concentration and MR signal can then be related to
relaxivity. We describe synthesis and
characterization of a fluorine-18 labeled, gadolinium-based probe with pH
dependent relaxivity. Simultaneous
MR-PET imaging indicates a strong correspondence between pH calculated from
the joint image analysis and pH measured by electrode.