Longitudinal Cell Tracking and Simultaneous Monitoring of Tissue Regeneration after Cell Treatment of Natural Tendon Disease by Low-Field Magnetic Resonance Imaging
Microscopic and magnetic resonance images of labelled cells. Prussian blue staining of intracellular iron oxide particles (a); orange fluorescence of the intracellular rhodamine, nuclei in blue (b); T1-weighted (T1w) and -weighted () gradient echo (GRE) images (c) of the gel phantoms 1 week (1 wk), 2 weeks (2 wks), and 4 weeks (4 wks) after cell labelling. The upper wells in each gel contain 106 labelled cells (MSC), the lower wells 105 labelled cells (MSC). The shape of the wells is indicated exemplarily by circles in the first upper image in (c). The hypointense artefacts caused by the labelled cells are visible in both sequences until 2 weeks after labelling. Here, the higher cell concentration led to artefacts exceeding the shape of the well in which the MSC were localized. Four weeks after labelling, no artefacts were seen in the T1w GRE sequence and only 106 MSC induced weak hypointense artefacts in the GRE sequence.