![]() ![]() 4 GBCAs are typically excreted by the kidneys, with an elimination half-life of approximately 90 minutes in patients with normal renal function. 2 After intravenous administration, GBCAs distribute into accessible extracellular spaces, with a distribution half-life of approximately 10 minutes. ![]() ![]() The chelation of gadolinium to organic ligands promotes bio-distribution within the extracellular interstitial space while enhancing renal filtration. While differences do exist among the gadolinium compounds in terms of various physicochemical characteristics, stability, concentration and relaxivity appear to have a major clinical impact. They can be categorised by their chemical structures into linear and macrocyclic agents and further subdivided by their charge (ionic or non-ionic). GBCAs consist of the active substance gadolinium and a chelating agent. Molecular Structure and Physicochemical Characteristics In response to the growing interest in this topic, this article will address the differences between gadolinium-based MRI contrast agents with regard to their molecular structure and physicochemical properties, providing evidence of the advantages of some compounds in terms of stability, relaxivity and concentration. Greater importance has recently been placed on GBCAs and chelate stability, particularly with the possible association between the development of nephrogenic systemic fibrosis (NSF) in patients with kidney failure. The differences between the molecular structures of the gadolinium chelates affect their physicochemical characteristics. These contrast agents have been used extensively in a large range of indications, particularly central nervous system examinations, as well as neurodegenerative diseases and tumoural disease processes, among others.Ĭontrast enhancement has enabled improved tissue contrast and lesion characterisation and more sensitive detection of even very small lesions. Since the original conception and introduction of magnetic resonance imaging (MRI) gadolinium-based contrast agents (GBCAs) in the 1980s, many such contrast agents have been approved for use in contrast-enhanced MRI. ![]() Gadolinium-based contrast agent (GBCA), contrast-enhanced magnetic resonance imaging, stability, relaxivity, concentration Article: 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. 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. Gadobutrol, gadobenate and gadoxetic acid have relatively high relaxivities. Relaxivity and concentration are contributing factors to the level of enhancement that can be achieved with any given GBCA. GBCAs can be categorised into three stability classes: non-ionic linear agents, ionic linear agents and macrocyclic agents, in order of increasing stability. The stability, concentration and relaxivity of a GBCA can have a major impact on clinical efficacy. 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. ![]()
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