19F MR Techniques Augment Quantitative Molecular Imaging with Paramagnetic Perfluorocarbon Nanoparticles at 1.5T
Caruthers S, Lamerichs R, Winter P, Neubauer A, Hockett F, Wickline S, Lanza G, Gaffney P, Scott M
Washington University School of Medicine, Philips Medical Systems
Relative to proton-based MR molecular imaging, fluorine MRI/MRS offer additional possibilities in quantifying agents and discerning multiple tracers. Herein, we demonstrate 19F quantification techniques as compared to T1 measurements using fibrin-targeted paramagnetic perfluorocarbon nanoparticles in clot phantoms. Two fibrin-targeted nanoparticle emulsions were prepared using perfluoro-15-crown-5-ether (CE) or perfluorooctylbromide and applied to clots in varying mixtures. Only the CE particles incorporated gadolinium. With proton imaging, signal intensity and T1 values behaved as expected with CE concentration. Signal intensity on both 19F imaging and spectroscopy correlated well with nanoparticle concentration. Additionally, the different perfluorocarbons were imaged and quantified independently.