A Perspective on Cell Tracking with Magnetic Particle Imaging

Abstract

Many labs have been developing cellular magnetic resonance imaging (MRI), using both superparamagnetic iron oxide nanoparticles (SPIONs) and fluorine-19 ( 19 F)-based cell labels, to track immune and stem cells used for cellular therapies. Although SPION-based MRI cell tracking has very high sensitivity for cell detection, SPIONs are indirectly detected owing to relaxation effects on protons, producing negative magnetic resonance contrast with low signal specificity. Therefore, it is not possible to reliably quantify the local tissue concentration of SPION particles, and cell number cannot be determined. 19 F-based cell tracking has high specificity for perfluorocarbon-labeled cells, and 19 F signal is directly related to cell number. However, 19 F MRI has low sensitivity. Magnetic particle imaging (MPI) is a new imaging modality that directly detects SPIONs. SPION-based cell tracking using MPI displays great potential for overcoming the challenges of MRI-based cell tracking, allowing for both high cellular sensitivity and specificity, and quantification of SPION-labeled cell number. Here we describe nanoparticle and MPI system factors that influence MPI sensitivity and resolution, quantification methods, and give our perspective on testing and applying MPI for cell tracking.

Intra-Arterial Stem Cell Transplantation in Experimental Stroke in Rats: Real-Time MR Visualization of Transplanted Cells Starting With Their First Pass Through the Brain With Regard to the Therapeutic Action

“…Among all imaging modalities for stem/progenitor cells tracking in live animals ( von der Haar et al, 2015 ; Bulte and Daldrup-Link, 2018 ), MRI combined with the labeling of cells with superparamagnetic iron oxide micro- and nanoparticles is one of the most convenient and relevant. In recent decades, this method has been widely used in basic and clinical studies ( Bulte, 2009 ; Namestnikova et al, 2017b ; Sehl et al, 2020 ). However, in the majority of investigations labeled cells were detected only after the completing of transplantation.…”

The Potential Application of Magnetic Nanoparticles for Liver Fibrosis Theranostics

“…Moreover, magnetic particle imaging (MPI) is capable of directly imaging the distribution of MNPs. The technique was first represented in 2005 (Nikitin et al, 2018;Sehl et al, 2020). Since MPI exhibits enhanced temporal and spatial resolution compared with MRI, it may represent a promising system for the detection of liver diseases (Sehl et al, 2020).…”

“…The technique was first represented in 2005 (Nikitin et al, 2018;Sehl et al, 2020). Since MPI exhibits enhanced temporal and spatial resolution compared with MRI, it may represent a promising system for the detection of liver diseases (Sehl et al, 2020). The use of MNPs as biosensors might be another interesting methodology (Gessner et al, 2021).…”

Magnetic Particle Imaging: Current and Future Applications, Magnetic Nanoparticle Synthesis Methods and Safety Measures

“…Additionally, on the topic of practical implementation, there are certainly situations where MPI alone is insufficient. These situations include the need for morphological description, which is typically not provided by tracer-based imaging modalities and requires overlay with a CT or MR image [ 8 , 42 , 43 ].…”