Short name: Gd-DTPA, generic name: Gadopentetate dimeglumine, chemical compound: Gadolinium-diethylenetriaminepentaacetic acid
Gadopentetate dimeglumine was introduced in 1981, as the first paramagnetic MRI contrast agent (ionic). The Gd-induced dipole dipole interactions lead to shortening of T1, which results in contrast enhancement on T1 weighted images. The used metal ion Gd3+ (gadolinium) is toxic, and therefore bound in the renally excreted DTPA chelate, a very stable complex. The Gd-complex also induce susceptibility effects, as a result of the magnetic field gradient between the contrast agent in the blood vessels and the surrounding tissue, that lead to shortening of T2 or T2*.
Following intravenous administration, the compound is distributed rapidly in the extracellular space and is eliminated unchanged by glomerular filtration via the kidneys. Up to 6 hours, post injection an average of 83% of the dose is eliminated renal.

See also Magnevist®, Gadolinium and Contrast Agents.

Gd-DTPA (Magnevist® Enteral) for gastrointestinal use with 1 mmolar required concentration.

See also Positive Oral Contrast Agents.

Short name: Gd-DTPA mesoporphyrin, generic name: gadophrin, central moiety: Gd2+
Gadophrin is a substance under development (Bayer Schering Pharma AG) as a positive enhancing myocardium- and necrosis- targeted MRI contrast agent.

See also Metalloporphyrins and Necrosis Avid Contrast Agent.

Short name: Gd-DOTA, generic name: Gadoterate meglumine
Dotarem / [ Artirem® ] A paramagnetic MRI contrast agent for intravenous use. This agent is used as a routine clinical tool to reveal anatomical details in vivo and to detect lesions for diagnosis.

See also Contrast Agents.

Short name: Gd-HP-DO3A, generic name: Gadoteridol injection, chemical compound: Gd-1,4,7-tris(carbonylmethyl)-10-(2'-hydroxypropyl)-1,4,7,10-tetraazacyclododecane
(ProHance®) A nonionic MRI contrast agent with a low molecular weight complex of gadolinium (macrocyclic chelate, which tightly binds the Gd atom).
Gadoteridol does not cross the blood brain barrier. If the barrier is damaged, gadoteridol will penetrate into lesions such as tumors. It also highlights areas of increased vascularity so it has been used to improve the delimitation of lesions elsewhere in the body.
Apart from its paramagnetic effects, gadoteridol has no pharmacological activity in the body. After intravenous injection, most of the dose is excreted unchanged in the urine within 24 hours.

See also Contrast Agents and ProHance®.