19F magnetic resonance imaging of endogenous macrophages in inflammation

In this article, we review the use of 19F MRI (magnetic resonance imaging) for in vivo tracking of monocytes and macrophages in the course of tissue inflammation. Emulsified perfluorocarbons (PFCs) are preferentially phagocytized by monocytes/macrophages and are readily detected by 19F MRI. Because of the lack of any 19F background in the body, observed signals are robust and exhibit an excellent degree of specificity. As a consequence of progressive infiltration of the labeled immunocompetent cells into inflamed areas, foci of inflammation can be localized as hot spots by simultaneous acquisition of morphologically matched proton (1H) and fluorine (19F) MRI. The identification of inflammation by 19F MRIat a time when the inflammatory cascade is initiatedopens the possibility for an early detection and more timely therapeutic intervention. Since signal intensity in the 19F images reflects the severity of inflammation, this approach is also suitable to monitor the efficacy of pharmaceutical treatment. Because PFCs are biochemically inert and the fluorine nucleus exhibits high magnetic resonance (MR) sensitivity, 19F MRI may be applicable for clinical inflammation imaging. WIREs Nanomed Nanobiotechnol 2012, 4:329343. doi: 10.1002/wnan.1163