Relaxation induced by ferritin: a better understanding for an improved MRI iron quantification

Ferritin, the iron storing protein, is known to darken T2-weighted MRI. This darkening can be used to non-invasively measure iron content. However, ferritin's behavior is not the same in tissue as in solution, a discrepancy that remains unexplained by the recently developed theory matching the NMR properties of ferritin solutions. A better understanding of the relaxation induced by ferritin in tissue could help for the development of new MRI protocols of iron quantification. In this short review, the main relaxation properties of ferritin in solution and in tissue are presented together with a discussion of the possible reasons for the faster transverse relaxation observed in tissues.