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

Iron oxide nanoparticles (IONPs) have been identified as a promising class of compounds that can enhance contrast in MRI (magnetic resonance imaging) 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 subsequently coated with a layer of dextran. The nanoparticles underwent characterization using techniques such as TEM (transmission electron microscopy), vibrating sample magnetometry (VSM), and XRD (X-ray diffraction). 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 at 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 exhibited an average size of 15 ± 3 nm, an inverse spinel crystal structure, and displayed magnetic characteristics indicative of superparamagnetism with a 65 ± 5 emu/g saturation magnetization. MRI scans revealed significant signal intensity changes and contrast enhancement in the liver, spleen, and kidneys after IONP administration. The 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. In conclusion, dextran-coated IONPs demonstrated effective T2 contrast enhancement in MRI of rabbits, particularly in the liver and spleen. The prolonged retention of the nanoparticles in these organs makes them suitable for long-term imaging studies. However, the rapid clearance from the kidneys may limit their application for kidney imaging. [ABSTRACT FROM AUTHOR]