Quantitative molecular imaging of angiogenesis-targeted fluorinated nanoparticles: new approaches for B 1 -mapping compensation for 19 F-MRI

Background Quantitative MR molecular imaging allows for the detection of targeted contrast agents to diagnose disease states and monitor response to therapy, such as anti-angiogenic therapy in atherosclerosis and cancer with aνb3-integrin targeted perfluorocarbon (PFC) nanoparticles. Recently, 19 FM R using a 19 F/ 1 H dual-tuned RF coil has been utilized to directly image and quantify the fluorinated core of these PFC nanoparticle (NP) emulsions. However, low concentrations of these fluorine agents in the body, in conjunction with varying RF coil sensitivity profiles (B1field inhomogeneities) raise obstacles to accurate quantification. This study presents a strategy to more accurately quantify the sparse 19 Fs ignal from PFC NP emulsions with a 1 H image-based Actual Flip-angle Imaging (AFI) B1-mapping correction to the 19 Fa nd 1 Hi mages.