Are All Gadolinium-based Contrast Agents Similar? The Importance of High Stability, High Relaxivity and High Concentration

Gadolinium-based contrast agents (GBCAs) are commonly used to enhance image acquisition via magnetic resonance imaging, but they differ in their physicochemical characteristics and therefore their function. The stability, concentration and relaxivity of a GBCA can have a major impact on clinical efficacy. Stability is related to safety. GBCAs can be categorised into three stability classes: non-ionic linear agents, ionic linear agents and macrocyclic agents, in order of increasing stability. Relaxivity and concentration are contributing factors to the level of enhancement that can be achieved with any given GBCA. Gadobutrol, gadobenate and gadoxetic acid have relatively high relaxivities. Among these compounds, only gadobutrol is commercially available at a higher concentration of 1.0M, whereas the others are used at a standard concentration of 0.5M. With high stability, relaxivity and concentration, gadobutrol has been shown in a number of clinical studies to be safe while improving image enhancement with increased conspicuity and sensitivity over other commonly used GBCAs.