Gadolinium Deposition in Bone Tissues After Contrast-enhanced Magnetic Resonance Imaging: A Comprehensive Review.

Over the past 15 years, significant advancements have been made in understanding the pharmacology and toxicology of gadolinium-based contrast agents (GBCAs), widely used in magnetic resonance imaging (MRI). This review focuses on the fate of gadolinium cation (Gd 3+ ) in bone tissues. The evidence indicates that Gd 3+ can persist in bone for extended periods, with higher retention observed for GBCAs with linear ligand structures as opposed to macrocyclic ones. The prolonged presence of Gd, with a significant proportion in species other than the initial intact injected GBCA form, raises concerns about potential toxicological effects, although no direct clinical consequences on bone physiology have been reported so far. This review discusses the complex interactions between Gd 3+ and bone matrix components, such as hydroxyapatite, collagen, and proteoglycans, which might contribute to the mechanisms of Gd retention. It also explores the potential for Gd to interfere with bone remodelling processes and cellular functions, as suggested by in vitro studies, and in comparison with that known for other rare earth elements (REE).