Gadolinium

Regarding the magnetic resonance imaging (MRI) contrast medium gadolinium, which one of the following statements is TRUE?

a) Gadolinium is usually administered as the soluble salt, gadolinium chloride

b) Unlike X-ray contrast media, gadolinium is safe to administer to patients with stage

3 chronic kidney disease

c) Gadolinium is paramagnetic in its Gd3+ state

d) The main role in MRI for gadolinium is to enhance the brightness of neural tissue

e) Gadolinium produces a similar incidence of severe allergic reactions compared to

X-ray contrast media

Answer: c

Explanation

Gadolinium is a metal element of the lanthanide group, used in MRI scanning as a

contrast agent. Gadolinium stays in intact blood vessels so will make the circulatory

system, vascular organs or areas of active bleeding appear brighter. It is usually

administered as a chelate with organic molecules such as diethylenetriaminepentaacetic

acid (DTPA). Gadolinium chloride, acetate or sulphate have low solubility at

physiological pH and are toxic. Gadolinium is paramagnetic in its Gd3+ state and it is in

this form that it is used in MRI. Gadolinium has a half-life of 30 to 90 minutes and is

excreted through the kidneys. Severe side effects from gadolinium administration are

extremely uncommon. There have been around 300 million administrations of gadolinium

over the last 30 years. There have been about 200 reports of a skin condition

called nephrogenic systemic fibrosis, mainly in patients with kidney disease following

the use of gadolinium for MRI scanning. Gadolinium is not nephrotoxic to healthy

patients but has been found to produce acute renal failure in 12% of patients with preexisting stage 3 or 4 chronic kidney disease (glomerular filtration rate <60 mL/min/1.73m2). The incidence of severe allergic reactions is low at 1 per 18 000 administrations compared to 1 per 1000 X-ray contrast administrations.

Reference

Ergün I, Keven K, Uruç I, et al. The safety of gadolinium in patients with stage 3 and 4

renal failure. Nephrol Dial Transplant 2006; 21(3): 697–700.