Fig. 5

Parameters of MRI image analysis. a Reduction in the cluster area of labeled MSCs with time. b 24-h (1 d) and 48-h (2 d) displacement of SPIONs-MSCs increased significantly under magnetic field (*P < 0.05, **P < 0.001). c CNR was the highest at 24 h, and an MRI shows obvious increase in the SPIONs-MSCs + magnetic field group. d SNR increased in the SPIONs-MSCs + magnetic field group by 24 h, and was high in both groups by 7 d