Mohsen Shoja - MSc in Radiobiology and Radiation protection, Instructor in department of Radiology, School of Allied Medical Sciences, Semnan University of Medical Sciences, Semnan, Iran
Rasool Alipouri - BS in Radiology, Student Research Committee, School of Allied Medical Sciences, Semnan University of Medical Sciences, Semnan, Iran

Introduction: Magnetic nanoparticles (MNPs) possess unique magnetic properties and the ability to function at the cellular and molecular level of biological interactions making them an attractive platform as contrast agents for magnetic resonance imaging (MRI). MNPs with higher magnetic moments, non-fouling surfaces, and increased functionalities are now being developed for applications in the detection, diagnosis, and treatment of malignant tumors, cardiovascular disease, and neurological disease.This review provides a background on applications of MNPs as MR imaging contrast agents and an overview of the recent developments in this area of research. methods: The keywords magnetic resonance imaging, nanoparticles, contrast agents were searched in PubMed, Google scholar and Web of science for this review. Finally articles from 2014 to 2018 were evaluated. Result: MRI is a powerful method in the early diagnosis of diseases. The commonly used Gadolinium based contrast agents are paramagnetic in medical and biological applications. As an extension to the development of ion chelates, many researchers have focused on ionic nanostructure-based T1 contrast agents that incorporate ion chelates onto or into nano-sized carriers to increase the relaxivity. Nanoparticle-based MRI contrast agents play important roles in improving MRI sensitivity, and they are applied in broad criteria from T1-weighted imaging, T2-weighted imaging. Their high surface-to-volume ratio enables facile surface modification. Recently superparamagnetic iron oxide nanoparticles (SPIONs) have been discovered to influence MRI contrast as well. The material of the core as well as the core’s size and shape of a superpara and ferromagnetic particle mainly define its magnetic properties. Since the spin relaxation time of water protons differs, whether magnetic nanoparticles are bound to a target or not.Conclusion: Nanoparticle-based MRI contrast agents with low risk and complementary contrast would be alternatives for future cancer studies.

Magnetic Nanoparticles, Contrast Agents, Magnetic Resonance Imaging, Diagnosis Diseases