Sagittal MR Imaging of pellets of 2 × 106 unlabeled (left) and labeled ADSCs (0.5, 1, and 2 mM Gadoteridol) in test tubes: (a) T1W SE 500/17 (TR/TE) at 7 T, (b) T1W SE 500/13 (TR/TE) at 1 T; panels (c, d) show corresponding T1 relaxation times of labeled and unlabeled ADSCs, determined based on IR sequences, as well as corresponding Gd content of the labeled cells, as measured by inductively coupled plasma (ICP)