T2*-weighted image showing USPIO-labeled immune cell infiltration in transplanted hearts. a, b, Isografts; c, d, Grade III allografts; and e, Grade II allograft. Patches of hypointensity indicate areas with high numbers of USPIO-labeled immune cells. The upper left corner of the isograft in Panel a has susceptibility artifact from the abdomen. LV—left ventricle; RV—right ventricle. (From Wu et al. [22•]; with permission)