title: MRI visualization of a single 15 µm navigable imaging agent and future microrobot.
abstract: In magnetic resonance imaging (MRI), the susceptibility-based contrast provides a way to amplify the effects of a magnetic microparticle, whereas its volume is largely inferior to the spatial resolution of the system. This concept presents an approach to visualization by means of susceptibility artifact using ferromagnetic microparticles. In this work, the amount of the susceptibility artifact was investigated using a simulation model and in vitro experiments on stainless steel microspheres measuring 40, 20 and 15 microm in diameter. The results showed that using a clinical MRI system, a single 15 microm microsphere is detectable in gradient-echo scans. The extent of the susceptibility artifact was found to be related to the scan parameters and the particles' sizes. Since the same ferromagnetic microparticle can be used for MRI-based propulsion, these results suggest several potential applications for navigable agents and microrobots involved in therapy, diagnostics, and imaging inside the microvascular network of the human body.
authors.affiliation: École Polytechnique Montréal, QC, H3C 3A7, Canada. nina.olamaei@polymtl.ca
authors.forename: N
authors.initials: N
authors.lastname: Olamaei
authors.forename: F
authors.initials: F
authors.lastname: Cheriet
authors.forename: G
authors.initials: G
authors.lastname: Beaudoin
authors.forename: S
authors.initials: S
authors.lastname: Martel
mesh_terms: D007501:Iron; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008280:Magnetics; D008863:Microspheres; D008904:Miniaturization; D012371:Robotics
chemical_list: D007501:Iron