Gadolinium For Radiologist

 This is a supplement to our previous post on  MRI contrast media, submitted by Dr MGK Murthy.

• Chemical element with Atomic No 64 in periodic table in lanthanide series  
• Atomic weight of 157.25g.mol_1 
• malleable 
• world produces pure gadolinium of appx 400 tonnes  
• because of nature of high absorption of neutrons used in nuclear medicine 
• because of paramagentic properties used in MRI for contrast after chelating, as free gadolinum is toxic

Recommendation with no bias for any specific chemical or marketing production houses :

 

• If the patient has normal renal function, use of any gadolinium compound makes no difference as renal excretion gets it out of the body 
• If the patient has moderate renal dysfunction, use of less dose, interval of at least 7days between repeat doses and preferable use of macromolecule varities would help 
• If the patient has severe renal dysfunction, use of macromolecules would be advised
• In extremes of age and lactating mothers , macromolecules is recommended
• If the patient has Calculated GFR of < 30ml/mt/1.73m2, Gadolinuim use is prohibited
• In pregnancy , Gadolinium is contraindicated

MRI contrast agents - Review Points

Teaching points


Submitted by Dr MGK Murthy
• Definition: Basically Gadolinium containing chelates

• Two types-“macrocyclic” chelates where Gd3+ is caged in the pre-organized cavity of the ligand, and “open- chain” (or “linear”) chelates.

• Taking in to account thermodynamic and kinetic stability factors ,macrocyclic chelatesare more stable particularly if they are ionic

• Exact cause of Nephrogenic Systemic Fibrosis is not known, but is postulated free Gd released in to circulation is responsible

• No patient with normal renal function has developed NSF

• So far about approximately 200 million patients have received MRI contrast

• Till 1997 no major contrast reaction was reported

• Between 1997 and 2009, 850 cases are reported all over the world (none from India)

• Toxic free Gd +3 from chelates is attached to fibrocytes leading to fibrosis

• Other factors possibly playing role are proinflammatory complexes, vascular injuries, high serum calcium etc


Various varieties of Gd Contrast agents in the market are :

A) Macrocyclic compounds with Trade names in brackets

1.Gd -DOTA (DOTAREM) (Guerbet company)

2.Gd-HP-DO3A (PROHANCE)(Bracco)

3.GD-BT-DO3A(GADOVIST)(Bayer Schering)


B) Open Chain Chelates

1.Gd-DTPA (MAGNEVIST)(Bayer Schering)(1stGdcontrast )

2.Gd-BOPTA(MULTIHANCE)(Bracco)

3.Gd-EOBDTPA(PRIMOVIST)(Bayer Schering)

4.MS325(ABLAVAR)(LantheusMedical imaging company)

5.Gd DTPA BMA(OMNISCAN)(GE)

6.GdDTPABMEA(OPTIMARK)(Mallinckrodt)



Recommendation for use in general

1. Use when necessary with cost benefit/Risk ratio calculation

2. Preferably screen for Renal dysfunction and calculated Glomerular filtration rate of >30ml/mt/1.73 m2 is needed before injecting the Gd

3. In Pregnancy all contrast agents are contraindicated as teratogenicity is not known

4. In Neonates less than 4 weeks open chain chelates contraindicated and macrocyclic variety could be given with minimum dosage

5. Always keep at least 7 days between administrations

6. Patients more than 65 yrs age need to be particularly screened for Renal dysfunction

7. Liver Transplant patients and Breast feeding mothers could receive minimum dose of macrocyclic varieties

8. Generally classified by European medical agency (EMA)as

(a) High Risk group-- Omniscan®

- Optimark® - Magnevist

(b)Moderate risk group-Primovist and Multihance

[c] Low Risk Group-Dotarem, prohance and Gadovist

9. High Strength magnets particularly 3.0 T could reduce the quantity of contrast injected

10. Hemodialysis is not recommended if renal dysfunction patients have received gadolinium, though patients on hemodialysis have benefitted by continuing it