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Abstract #4497

In Vivo LipoCEST CA Accumulation Around U87 Mice Brain Tumor Demonstrated by In Vivo CEST MRI & Ex Vivo Fluorescence Microscopy

Julien Flament1, Franoise Geffroy1, Boucif Djema1, Benoit Theze2, Aline Perrin1, Christelle Medina3, Caroline Robic3, Marc Port3, Franck Lethimonnier1, Gilles Bloch1, Denis Le Bihan1, Fawzi Boumezbeur1

1NeuroSpin, I2BM, DSV, Commissariat l'Energie Atomique, Gif-sur-Yvette, France; 2SHFJ, I2BM, DSV, Commissariat l'Energie Atomique, Gif-sur-Yvette, France; 3Guerbet, Research Division, Roissy-Charles de Gaulle, France

LipoCEST are a promising class of contrast agents for MR-based molecular imaging. However, recently similar PEGylated stealth paramagnetic liposomes have been shown to be avidly taken up by macrophages. For LipoCEST CA, similar cellular uptake could be extremely detrimental for its detection in vivo. In this study, we injected i.v 10mL/kg b.w. of PEGylated LipoCEST CA with rhodamine on its surface and managed to detect its accumulation around a U87 mice brain tumor in vivo using CEST-MRI. This result constitutes to our knowledge the first visualization of paramagnetic LipoCEST CA after i.v injection confirmed by ex vivo fluorescence microscopy.