Vahe Zohrabian
Gadolinium-based contrast agents (GBCAs) have traditionally been considered very safe. The incidence of life-threatening adverse reactions occurring within 24 hours of GBCA administration is extremely low. Nephrogenic systemic fibrosis, a rare clinical entity first described in 2006, has essentially been eradicated given changes in practice in the use of GBCAs in patients with renal insufficiency. More recently, concerns have arisen over the safety of GBCAs as scientific evidence proving the retention of gadolinium in human tissues continues to grow. This has led to the classification of GBCAs according to their stability or the structure of their chelated forms (linear or macrocyclic), which dictates the rate of dissociation of free gadolinium (Gd3+) and the likelihood of transmetallation. It is widely accepted that macrocyclic GBCAs (eg, gadoterate meglumine, gadobutrol, gadoteridol) are more stable and are retained less in tissues when compared with linear GBCAs (eg, gadodiamide, gadoversetamide, gadopentate dimeglumine).
The incidental deposition of GBCAs in the brain has been known since 2014, and since then, multiple studies have confirmed the relationship between multiple administrations of linear GBCAs and T1 hyperintensity in the dentate nucleus and globus pallidus in both adult and pediatric patients with normal renal function. Studies have also linked GBCA administration and T1 hyperintensity in other structures of the brain, such as the pulvinar of the thalamus, precentral and postcentral cortex, and calcarine cortex. Unfortunately, the underlying pathophysiology for GBCA deposition in the brain is poorly understood. Luckily, no strong scientific evidence exists to date for the harmful clinical effects of GBCA accumulation in the brain. The current issue of the AJNR News Digest highlights several recently published studies confirming the retention of gadolinium in the human brain and brings to light topics for future investigation.
Image from: Bolles GM, Yazdani M, Stalcup ST, et al. Development of High Signal Intensity within the Globus Pallidus and Dentate Nucleus following Multiple Administrations of Gadobenate Dimeglumine.