Molecular MRI of Neuroinflammation: Time to Overcome the Translational Roadblock

The ability to detect a molecular target in the central nervous system non-invasively and at high spatial resolution using magnetic resonance imaging (MRI) has attracted the interest of researchers for several decades. Yet, molecular MRI studies remain restricted to the preclinical stage and the path to clinical translation remains unclear. The focus of molecular MRI of neuroinflammation has moved from parenchymal to vascular targets, that are more easily reachable by intravenously injected probes. This has allowed the use of large superparamagnetic probes, such as micro-sized particles of iron oxide (MPIO), that dramatically improved the sensitivity of molecular MRI compared to smaller contrast agents. In particular, recent studies demonstrated the feasibility of unraveling inflammation in the brain by MRI using MPIO able to bind activated endothelial cells with potential applications in neurovascular, neuroinflammatory and neurodegenerative disorders. In the present review, we present the most striking advances in the field and the remaining challenges that must be overcome before clinical use of molecular MRI of neuroinflammation. This article is part of a Special Issue entitled: Brain imaging (c) 2021 IBRO. Published by Elsevier Ltd. All rights reserved.

Automated summary

The use of magnetic resonance imaging (MRI) to detect molecular targets in the central nervous system non-invasively has drawn interest for many years. Recent advances in using large superparamagnetic probes like micro-sized particles of iron oxide (MPIO) have significantly improved the sensitivity of molecular MRI in neuroinflammation studies.