PEGylated Ultrasmall Iron Oxide Nanoparticles as MRI Contrast Agents for Vascular Imaging and Real-Time Monitoring.

Accurate imaging evaluations of pre- and post-treatment of cardiovascular diseases are pivotal for effective clinical interventions and improved patient outcomes. However, current imaging methods lack real-time monitoring capabilities with a high contrast and resolution during treatments. This study introduces PEGylated ultrasmall iron oxide nanoparticles (PUSIONPs), which have undergone comprehensive safety evaluations, boasting an r1 value of 6.31 mM-1 s-1, for contrast-enhanced magnetic resonance angiography (MRA). Systematic comparisons against common clinical methods in rabbits reveal that PUSIONPs-enhanced MRA exhibited improved vascular contrast, clearer vascular boundaries, and superior vessel resolution. Moreover, owing to their nanosize, PUSIONPs demonstrate significantly prolonged blood circulation compared to small molecular contrast agents such as Magnevist and Ultravist. This extended circulation enables captivating real-time monitoring of thrombolysis treatment for up to 4 h in rabbit models postsingle contrast agent injection. Additionally, in larger animal models such as beagles and Bama minipigs, PUSIONPs-enhanced MRA also showcases superior contrast effects, boundary delineation, and microvessel visualization, underscoring their potential to transform cardiovascular imaging, particularly in real-time monitoring and high-resolution visualization during treatment processes.