title: Magnetic particle imaging: current developments and future directions.
abstract: Magnetic particle imaging (MPI) is a novel imaging method that was first proposed by Gleich and Weizenecker in 2005. Applying static and dynamic magnetic fields, MPI exploits the unique characteristics of superparamagnetic iron oxide nanoparticles (SPIONs). The SPIONs' response allows a three-dimensional visualization of their distribution in space with a superb contrast, a very high temporal and good spatial resolution. Essentially, it is the SPIONs' superparamagnetic characteristics, the fact that they are magnetically saturable, and the harmonic composition of the SPIONs' response that make MPI possible at all. As SPIONs are the essential element of MPI, the development of customized nanoparticles is pursued with the greatest effort by many groups. Their objective is the creation of a SPION or a conglomerate of particles that will feature a much higher MPI performance than nanoparticles currently available commercially. A particle's MPI performance and suitability is characterized by parameters such as the strength of its MPI signal, its biocompatibility, or its pharmacokinetics. Some of the most important adjuster bolts to tune them are the particles' iron core and hydrodynamic diameter, their anisotropy, the composition of the particles' suspension, and their coating. As a three-dimensional, real-time imaging modality that is free of ionizing radiation, MPI appears ideally suited for applications such as vascular imaging and interventions as well as cellular and targeted imaging. A number of different theories and technical approaches on the way to the actual implementation of the basic concept of MPI have been seen in the last few years. Research groups around the world are working on different scanner geometries, from closed bore systems to single-sided scanners, and use reconstruction methods that are either based on actual calibration measurements or on theoretical models. This review aims at giving an overview of current developments and future directions in MPI about a decade after its first appearance.
authors.affiliation: Clinic for Radiology and Nuclear Medicine, University Hospital Schleswig Holstein, Campus Lübeck, Germany.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Panagiotopoulos
authors.affiliation: Clinic for Radiology and Nuclear Medicine, University Hospital Schleswig Holstein, Campus Lübeck, Germany.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Duschka
authors.affiliation: Institute of Medical Engineering, University of Lübeck, Lübeck, Germany.
authors.forename: Mandy
authors.initials: M
authors.lastname: Ahlborg
authors.affiliation: Institute of Medical Engineering, University of Lübeck, Lübeck, Germany.
authors.forename: Gael
authors.initials: G
authors.lastname: Bringout
authors.affiliation: Institute of Medical Engineering, University of Lübeck, Lübeck, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Debbeler
authors.affiliation: Institute of Medical Engineering, University of Lübeck, Lübeck, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Graeser
authors.affiliation: Institute of Medical Engineering, University of Lübeck, Lübeck, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Kaethner
authors.affiliation: Institute of Medical Engineering, University of Lübeck, Lübeck, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Lüdtke-Buzug
authors.affiliation: Institute of Medical Engineering, University of Lübeck, Lübeck, Germany.
authors.forename: Hanne
authors.initials: H
authors.lastname: Medimagh
authors.affiliation: Institute of Medical Engineering, University of Lübeck, Lübeck, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Stelzner
authors.affiliation: Institute of Medical Engineering, University of Lübeck, Lübeck, Germany.
authors.forename: Thorsten M
authors.initials: TM
authors.lastname: Buzug
authors.affiliation: Clinic for Radiology and Nuclear Medicine, University Hospital Schleswig Holstein, Campus Lübeck, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Barkhausen
authors.affiliation: Clinic for Radiology and Nuclear Medicine, University Hospital Schleswig Holstein, Campus Lübeck, Germany.
authors.forename: Florian M
authors.initials: FM
authors.lastname: Vogt
authors.affiliation: Clinic for Radiology and Nuclear Medicine, University Hospital Schleswig Holstein, Campus Lübeck, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Haegele
mesh_terms: D003952:Diagnostic Imaging / Q000379:methods / Q000639:trends; D058185:Magnetite Nanoparticles
chemical_list: D058185:Magnetite Nanoparticles
keywords: cardiovascular interventions; magnetic particle imaging; magnetic particle spectrometer; peripheral nerve stimulation; superparamagnetic iron oxide nanoparticles