Cell Tracking Using Magnetic Resonance Imaging

Due to its properties (see the section on magnetic resonance imaging), magnetic resonance imaging (MRI) can be used for the in vivo tracking of labeled cells. Cells can be labeled, for example, in vivo via direct intravenous administration of a contrast agent or in vitro via incubation with the contrast agent. However, endogenous iron can also influence the MRI signal. To date, it has not been possible to distinguish specifically between endogenous iron (⁵⁶Fe) and administered ION (also ⁵⁶Fe) due to signal overlap, which is particularly relevant for cell tracking studies. Therefore, in a project conducted in close collaboration with the Institute of Analytical Chemistry at the University of Münster, we are investigating the possibility of distinguishing between ION-applied iron and endogenous iron by using different iron isotopes in the ION core. This should enable specific tracking of the labeled cells. In addition to MRI, special mass spectrometry methods are also used for this purpose. IONs can be detected very sensitively using MRI, so that single-cell detection has recently even become possible. Time-lapse MRI is an innovative technology using IONs for cell tracking studies at the single-cell level, which we are investigating in another project. Through repetitive image acquisition, the goal is to enable not only a single-time, static image but also a dynamic representation of labeled immune cells. Since these immune cell dynamics change in response to a stimulus (such as inflammation), we are investigating whether this change can be visualized using MRI cell tracking.