Application of Iron Oxide Nanoparticles as MRI Contrast Enhancers: A study in Rabbits

Iron oxide nanoparticles (IONPs) are a promising class of compounds that can enhance contrast in MRI scans due to their superparamagnetic properties. This study evaluates the efficacy of dextran-coated IONPs as T2 contrast agents for MRI in a rabbit model. IONPs were prepared through a co-precipitation process and coated with a layer of dextran. The nanoparticles were characterized using techniques such as TEM, VSM, and XRD. New Zealand White rabbits (n=6) were used for in vivo MRI studies. IONPs (10 mg Fe/kg) were administered intravenously, and MRI scans (T1- and T2-weighted) were taken at baseline and various intervals (1, 4, and 24 h) after IONP administration. Signal intensity changes and contrast enhancement were analyzed in the liver, spleen, and kidneys. The IONPs showed significant signal intensity changes and contrast enhancement in the liver and spleen, with the maximum enhancement observed at 4 hours post-injection.. MRI scans revealed significant signal intensity changes and contrast enhancement in the liver, spleen, and kidneys after IONP administration. Maximum contrast enhancement was observed at 4 h post-injection, with a 60 ± 8% reduction in T2 signal intensity in the liver and a 45 ± 7% reduction in the spleen. The contrast enhancement persisted up to 24 h in the liver and spleen, while the kidneys showed lower contrast enhancement and rapid clearance of the nanoparticles. Nanoparticles demonstrated effective T2 contrast enhancement in rabbit MRI, making them suitable for long-term imaging studies. However, the rapid clearance from the kidneys may limit their application for kidney imaging.