Gadodiamid

Gadodiamid, also spelled gadodiamide, is a gadolinium-based contrast agent (GBCA) used in magnetic resonance imaging (MRI) to enhance tissue contrast. It is a linear, nonionic chelate in which gadolinium(III) is bound to a chelating ligand derived from diethylenetriamine pentaacetic acid, resulting in a water-soluble compound intended for intravenous administration.

As a GBCA, gadodiamide works by shortening the T1 relaxation times of nearby water protons, thereby improving the visibility of blood vessels, tumors, inflammatory processes, and other abnormalities on MRI. Typical dosing is around 0.1 mmol/kg, administered intravenously, with the exact dose and timing depending on the imaging protocol and clinical indication.

Safety and regulatory considerations have shaped the use of gadodiamide. It is one of the linear GBCAs associated with a risk of nephrogenic systemic fibrosis (NSF) in patients with severe renal impairment. Consequently, renal function assessment is recommended before administration, and alternative imaging methods or more stable macrocyclic GBCAs may be preferred in at-risk patients. In recent years, concerns about gadolinium retention in the brain and other tissues have led to labeling changes and cautions in many regulatory jurisdictions, although the clinical significance of such retention remains uncertain. Clinicians are advised to use the lowest efficacious dose, avoid repeat exposures when possible, and consider patient-specific factors when selecting a GBCA.

Gadodiamid has been marketed under various names and remains in use in some regions, but its application is guided by ongoing safety evaluations and regulatory guidance related to gadolinium-based contrast agents.