Figure 9
The MR dephasing effect. Theoretical and real case study of the dephasing effect of protons in the vicinity of a labeled cell in vivo. The upper panel shows the MR image of the lower hind limb of a mouse, intravenously injected with magnetically labeled macrophages, which form a typical four-lobed clover in the susceptibility-weighted scan (in-plane resolution of 39 ÎĽm), obtained with a 4.7 T scanner provided with a dedicated cryogenic probe. The bottom panel points out the impact of the echo time on the apparent cell size (top theoretical predictions and bottom real case study obtained at 9.4 T). The bottom panel has been adapted from reference (46).