Fast perfluorocarbon imaging using ¹⁹F U‐FLARE

The application of an ultra‐fast low angle RARE technique for the ¹⁹F imaging of perfluorocarbons (PFCs) used as temporary blood substitutes is described. This sequence is attractive for fast ¹⁹F imaging studies that measure the biodistribution of PFCs in vivo, due to its high signal‐to‐noise ratio. Extensions of this technique for the chemical shift selective measurement of fluorine T₁ values are presented. Using the linear dependence between the oxygen partial pressure (pO₂) and the T₁ relaxation rate of PFC resonances this technique makes possible the fast in vivo measurement of oxygen tension. Using the sequence in a diffusion sensitized form ¹⁹F measurements of the diffusion constants of PFCs are also presented. Phantom experiments to test the methods, and in vivo images obtained in rat studies are given and discussed.