Frontiers in 19F-MR imaging: nanofluorides and 19F-CEST as novel extensions to the 19F-MRI toolbox

Fluorine-containing materials have enriched the field of molecular and cellular MRI with unambiguous and quantitative detection capabilities. The background-free hot-spot display and the large range of chemical shifts of the broad palette of F-19-formulations are now used for a variety of applications. The common features of these formulations are: (i) they are based on organic molecular backbones (i.e., organofluorines); and (ii) their F-19-MRI detectability relies on a well-defined and clearly observed F-19-MR signal. During the last few years, our lab aimed to expand the F-19-MR toolbox with new capabilities that were, thus far, not used in molecular and cellular F-19-MRI. This Feature Article summarizes our developments and implementations in the field of F-19-MRI emphasizing (i) the introduction of ultrasmall inorganic fluoride-based nanocrystals (nanofluorides) as nano-sized (<10 nm) agents for F-19-MRI, and (ii) the use of Chemical Exchange Saturation Transfer (CEST) in the F-19-MRI framework to indirectly amplify F-19-MR signals of otherwise-undetected fluorinated entities.

Automated summary

Fluorine-containing materials have greatly improved molecular and cellular MRI by providing clear and quantitative detection capabilities. These materials are based on organic molecular backbones and rely on well-defined fluorine MR signals. Recent developments include the use of ultrasmall inorganic nanocrystals as agents for F-19-MRI and the application of Chemical Exchange Saturation Transfer (CEST) to amplify signals of otherwise-undetected fluorinated entities.