Fast dynamic MPI cytometry

Abstract

We developed in vivo fast dynamic MPI “cytometry” to quantify and localize the accumulation of SPIO-labeled stem cells in different organs after intra-arterial injection on a time scale of minutes. Bone marrow-derived mesenchymal stem cells (MSCs) and superoxide dismutase 1 gene-corrected neural precursor cells (NPCs) were labeled with Resovist and injected into Rag2 mice using four separate injections. Whole body standard 2D/3D MPI scans were obtained, quantified and co-registered with CT. Using cell calibration fiducials, cells could be clearly visualized and quantified by MPI in vivo in the brain, liver, and lung. The cytometric ratio of the number of cells in the liver/lung vs. the brain was 1.5 for MSCs and 15.6 for NPCs, respectively, at 24 min post-injection. Fast dynamic MPI cytometry may find applications for optimizing the dose, volume, speed and route of administration when performing interventional cell therapy procedures in real-time.