Gadolinium tissue deposition in brain and bone.

Until recognition of the association of nephrogenic systemic fibrosis (NSF) and gadolinium based contrast agents (GBCA) in 2006, these agents were considered extremely safe and without major adverse effects. Even after the recognition of NSF, most physicians considered all GBCAs to be safe when used in patients with normal renal function. This belief has been called into question with the discovery by Kanda in 2014 that gadolinium (Gd) is deposited in brain tissue in patients with normal kidney function. Since that initial report, there have been a number of important studies analyzing the effects of various GBCAs in brain using MR T1 signal intensity measurements and postmortem tissue analyses with inductively coupled plasma mass spectrometry. From these our knowledge and understanding of some key issues surrounding these observations has rapidly evolved. This report reviews and summarizes many recent human and animal studies in combination with past studies to better understand Gd tissue deposition not only in brain but also in bone and skin. Brain tissue deposition was initially demonstrated to occur with less stable group 1 linear agents but recent postmortem studies now confirm that Gd deposition also occurs with more stable linear agents as well as with macrocyclic agents although at much lower levels. Although no adverse health effects have been documented to date, even for the group 1 agents that deposit Gd in higher amounts, the implications for possible unrecognized toxicity is discussed. Future studies are being pursued that may provide better understanding of the various chemical forms of Gd that are deposited in tissues. This may help elucidate relative risks of different types of agents, mechanisms involved and even recognition of potential downstream toxic effects.