Potential positive MRI contrast agent based on PVP-grafted superparamagnetic iron oxide nanoparticles with various repetition times

The present study aimed to evaluate the capability of synthesized and modified superparamagnetic iron oxide nanoparticles (SPIONs) as the positive contrast agent in magnetic resonance imaging (MRI) by investigating the effect of repetition time (TR) on the MRI signal intensity. SPIONs were synthesized using the co-precipitation method, and their surface was successfully modified with biocompatible poly (N-vinylpyrrolidone) (PVP). The effect of TR on the signal intensity (SI) of the PVP-grafted SPIONs was assessed in the spin-echo T1-weighted MRI images. The results indicated the maximum SI at the concentration of 400 µmol Fe/l with the TR of 800-2,200 milliseconds. Moreover, the maximum SI was observed at the concentration of 75 µmol Fe/l, where TR was within the range of 2,900-6,400 milliseconds. According to the results, in addition to their capability as negative MRI contrast agents, PVP-grafted SPIONs could be preferred positive contrast agents with specific imaging parameters and have the potential application for early cancer diagnosis and perfusion measurements.