Fig. 5.

MR phase shift and R2* relaxation rate as functions of the tissue susceptibility (all susceptibilities χ are given relative with respect to water). While the different susceptibilities of cortical gray and white matter cause a reversed sign of the phase shifts (a), they provide similar R2* rates (b). This may explain well the limited cortical magnitude contrast when compared to the phase contrast. (Note that the bars are not in scale with results of Table 1).