Recent applications of magnetic iron oxide nanoparticles for cerebral blood volume quantification in functional magnetic resonance imaging.

The use of iron oxide nanoparticles (IONPs) in magnetic resonance imaging (MRI) and the study of brain functions using MRI have been continuously evolving for more than 30 years. This contribution aims to explore the recent applications of magnetic IONPs in the study of the brain through functional MRI (fMRI), particularly focusing on their use in a specific parameter, that is, the cerebral blood volume (CBV), whose measurements are valued for their higher sensitivity and spatial specificity with respect to blood oxygen level-dependent (BOLD) fMRI analyses. This study will summarize the basis of the fMRI technique, explaining the types of experiments commonly conducted, the parameters involved, and discussing the main techniques that exploit magnetic nanoparticles and other materials as contrast agents, along with their potential applications in the imaging field. CBV measurements will be explained in general theoretical terms and compared with other methods. The key elements of magnetic nanoparticle production, including the most commonly used synthesis procedures and coating options, will be reported. Finally, the discussion will focus on how CBV-weighted (CBVw) images acquired using IONPs are currently being utilized in research.