Figure 5a:

(a) Mean tumor R2 was similar in FHC-FC and control group tumors before and immediately after remote injection of fibroblasts. Mean R2 increased in FHC-FC tumors 4 days after remote injection of CV1-FHC fibroblasts and remained higher than that at baseline and in control tumors at all subsequent time points. (b) Mean regional R2 showed preferential recruitment of CV1-FHC fibroblasts to rim of tumors as early as 2 days after remote injection, with minor migration into core of tumor. (c) Representative R2 maps of midtumor sections acquired 7 days after remote administration of either CV1 or CV1-FHC fibroblasts show heightened R2 values along rim of FHC-FC tumors because of recruitment of CV1-FHC cells. (d) Gradient-echo axial scout images (echo time, 2.58 msec) show hypointensity along rim of FHC-FC tumors (red arrows) that are not present in control tumors. (e) In vivo fluorescence imaging confirmed colocalization of signal from cancer cells with signal from CV1 cells, confirming recruitment of remotely administered fibroblasts to tumors. * = P < .05 vs core, † = P < .05 vs control, ‡ = P < .05 vs day 0, # = P < .05 vs day 2 after injection.