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Gadolinium

Frequently used as contrast agent for magnetic resonance imaging and angiography.

It is estimated that approximately 8.8 million MRI procedures utilizing gadolinium were performed in 2016.

Gadolinium based contrast agents contain the rare earth metal gadolinium chelated to linear or macro cystic organic ligands that provide a means of safely administering and excreting an otherwise toxic agent.

Not nephrogenic and rarely triggers allergic reactions.

Excellent safety profile with acute adverse reactions ranging from 0.07-2.4%, substantially lower than adverse events observed with iodinated contrast material used during CT or angiography.

Some chelates can interfere with arsenazo III dye and orthocresolphthalein commonly used laboratory reagents which can produce spurious low calcium levels during assays for serum calcium levels.

Most reactions are mild, including headache, nausea, dizziness, paresthesias, joint, cognitive and injection site pain.

Anaphylactic reactions are rare, 0.001-0.01%.

Associated with hypocalcemia in 4% of examinations and of these 59% of patients had calcium levels in the critically low range.

Increased dosage of the gadolinium, decreased time from administration of the agent, impaired renal clearance all associated with an increased risk of false hypocalcemia.

Course of associated hypocalcemia ranges from immediately after the gadolinium infusion until 24 hours later in patients with renal impairment.

Recommended method of following calcium levels after the administration of gadolinium during a study is to check the ionized calcium level.

Contraindicated in patients with acute kidney injury and in patients with severe kidney disease with a glomerular filtration rate of less than 30ml/min/ 1.73 meter squared-to minimize the risk of nephrogenic systemic fibrosis.

Nephrogenic systemic fibrosis is extremely rare in pateints studied with an eGFR of>30 mL/min/1.73 m2.

Exposure during pregnancy is associated with increased risk for rheumatologic, inflammatory, or infiltrative skin conditions,stillbirth or neonatal death.

MRI contrast medium gadolinium crosses the placenta should not be used during pregnancy.

Gadolinium is retained in minute amounts throughout the brain parenchyma after contrast enhanced MRI examinations, even in areas without T1 signal intensity changes.

May remain in the body for months two years after injection.

The extent of gadolinium retention correlates with cumulative gadolinium contrast agents dosage, chelation stability/lability.

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