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[摘要]：Monitoring of cell therapeutics in vivo is of major importance to estimate its efficacy. Here, we present a novel intracellular label for F-19 magnetic resonance imaging (MRI)-based cell tracking, which allows for noninvasive, longitudinal cell tracking without the use of radioisotopes. A key advantage of F-19 MRI is that it allows for absolute quantification of cell numbers directly from the MRI data. The F-19 label was tested in primary human monocyte-derived dendritic cells. These cells took up label effectively, resulting in a labeling of 1.7 +/- 0.1 x 10(13) F-19 atoms per cell, with a viability of 80 +/- 6%, without the need for electroporation or transfection agents. This results in a minimum detection sensitivity of about 2,000 cells/voxel at 7 T, comparable with gadolinium-labeled cells. Comparison of the detection sensitivity of cells labeled with F-19, iron oxide and gadolinium over typical tissue background showed that unambiguous detection of the F-19-labeled cells was simpler than with the contrast agents. The effect of the F-19 agent on cell function was minimal in the context of cell-based vaccines. From these data, we calculate that detection of 30,000 cells in vivo at 3 T with a reasonable signal to noise ratio for F-19 images would require less than 30 min with a conventional fast spin echo sequence, given a coil similar to the one used in this study. This is well within acceptable limits for clinical studies, and thus, we conclude that F-19 MRI for quantitative cell tracking in a clinical setting has great potential. |
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