“…Several genetic MRI reporting systems have been investigated, including divalent metal transporters [ 24 , 25 ], β-galactosidase [ 26 ], tyrosinase [ 27 ], transferrin receptor [ 28 ], magA [ 29 , 30 ] and ferritin [ 31 , 32 ]. Among these candidates, ferritin, which displays a high transverse relaxation rate by inducing the expression of the transferrin receptor and increasing iron uptake, has been widely used as a reproducible and functional MRI reporter in extensive molecular imaging studies [ 2 , 33 ].…”