Gadopentetic acid

Gadopentetic acid is one of the trade names for a gadolinium-based MRI contrast agent, usually administered as a salt of a complex of gadolinium with DTPA (diethylenetriaminepentacetate) with the chemical formula A₂[Gd(DTPA)(H₂O)]; when cation A is the protonated form of the amino sugar meglumine the salt goes under the name "gadopentetate dimeglumine". It was described in 1981 and introduced as the first MRI contrast agent in 1987. It is used to assist imaging of blood vessels and of inflamed or diseased tissue where the blood vessels become "leaky". It is often used when viewing intracranial lesions with abnormal vascularity or abnormalities in the blood–brain barrier. It is usually injected intravenously. Gd-DTPA is classed as an acyclic, ionic gadolinium contrast medium. Its paramagnetic property reduces the T1 relaxation time (and to some extent the T2 and T2* relaxation times) in NMR, which is the source of its clinical utility.