A Dual Modality Nanoparticle MRI/CT Contrast Agent with Enhanced T1 and T2 Relaxivity

Simon A. Lubek¹, Veronica Clavijo Jordan¹, Kevin M. Bennett¹

We report a dual MRI/CT protein based W-Fe nanoparticle contrast agent with high T₁ (4,497 mM^-1s^-1) and T₂ (458,143 mM^-1s^-1) per particle relaxivities. The T₁ relaxivities observed demonstrated a 58 fold increase over iron oxide particles. TEM results showed nanoparticles ranging from 9 to 13nm in diameter. Rat striatum MRI scans demonstrated the agent is detectable in vivo. Furthermore, a CT comparison demonstrated a 1.5 fold contrast increase as compared to iron oxide particles.