Hadamard-Type Pulse-Phase Encoding for Imaging of Multi-Resonant Fluorine-19 Nanoparticles in Targeted Molecular MRI

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

¹⁹F-MRI allows the direct quantification of nanoparticles (NP) or fluorinated drugs in molecular imaging. Previously, α _ν β ₃-integrin targeted NP have been shown to detect and quantify angiogenesis in tumor models. Towards human translation, clinically-relevant NP-substrates like perfluoro-octyl-bromide (PFOB) should be applied, but rich spectra and large chemical shifts (CS) add significant complexity. Many methods have been developed to manage CS-artifacts, but tradeoffs like long encoding time or a need for complex corrections remain. Herein, Hadamard-type pulse phase encoding is introduced in the CS domain as a robust and efficient method to detect multi-resonant ¹⁹F labels. Feasibility is demonstrated in vitro and in vivo for angiogenesis-targeted PFOB-NP in Vx2 tumor bearing rabbits.