Magnetic resonance imaging of iron-oxide labeled SK-Mel 28 human melanoma cells in the chick embryo using a clinical whole body MRI scanner

To evaluate advantages and limitations of magnetic resonance imaging (MRI) to monitor the migration of superparamagnetic iron oxide (SPIO) labeled cells in the chick embryo. Labeled human SK-Mel 28 melanoma cells were injected into the E2 chick embryo neural tube. Embryos were examined with a clinical 3 T MRI whole body system using 3D T*(2)-weighted sequences with isotropic spatial resolutions of 0.3-1.0 mm. MR-measurements of embryos were performed 2 - 16 days after cell injection. MRI findings were verified by dissection and histology. After injection, melanoma cells formed aggregations that were detectable in the neural tube as signal voids in MR images from day 2 after injection. Emigrating cells later left MRI detectable tracks. Aggregates that remained in the neural tube left label that was absorbed by glia cells. In E18 chick embryos, signals of haematopoiesis interfered with signals from cell labeling. It was shown that SK-Mel 28 cells will resume the neural crest pathways after injection into the embryonic micro-environment. SPIO cell labeling allows monitoring of transplanted melanoma cells during embryonic development. MRI using the standard clinical equipment promises to be valuable for high-sensitive monitoring of ex-vivo labeled cells in the chick embryo.