Target-Binding of Perfluoro-Carbon Nanoparticles Alters Optimal Imaging Parameters Using F-19 Molecular MRI: A Study Using Fast in Vitro Screening and in Vivo Tumor Models.

Jochen Keupp¹, Anne H. Schmieder², Samuel A. Wickline², Gregory M. Lanza², Shelton D. Caruthers²

Patient stratification using molecular MRI of angiogenesis could change standard of care in anti-angiogenic therapy. Previously, α _ν β ₃-integrin targeted nanoparticles (NP) have been shown to detect and quantify angiogenesis in small-animal tumor models based on ¹⁹F-MRI. These promising results using Perfluoro-Crown-Ether labels are currently translated to more clinically-relevant Perfluoro-Octyl-Bromide (PFOB) NP. The complex spectral properties of PFOB and the sensitivity to the target-binding process, as observed in this work, require a thorough optimization of imaging parameters on target. In vitro optimization on fibrin clots and in vivo detection of angiogenesis-targeted NP in the vasculature of Vx2-tumor bearing rabbits by ¹⁹F-MRI is demonstrated.