High-Contrast and Fast-Removable ¹⁹F-MRI Labels with Perfluoro-tert-Butyl Substituents

F-19 MRI is a unique technique for tracking and quantifying the indicator (F-19-MRI label) in vivo without the use of ionizing radiation. Here we report new F-19-MRI labels, which are compounds with perfluoro-tert-butyl groups: 1,2-bis(perfluoro-tert-butoxy)ethane (C10F18H4O2) and 1,3-bis(perfluoro-tert-butyl)propane (C11F18H6). Both substances contain 18 equivalent F-19 atoms, constituting 68.67 % and 71.25 % of the molecule, respectively. The emulsions with F-19 molecules were prepared and used in F-19 MRI studies in laboratory rats in vivo. The substances demonstrated high contrast properties, good biological inertness and the ability to be rapidly eliminated from the body. We showed that at a dose of 0.34 mg/g of body weight in rats, the time for complete elimination of C10F18H4O2 and C11F18H6 is & SIM;30 days. The results turned out to be promising for the use of the presented compounds in F-19 MRI applications, especially since they are quite easy to synthesize.